


Building A Hero!

by MKDremareRiser



Series: Building A Hero Universe [1]
Category: Kamen Rider Build, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Fusion, F/F, F/M, Gen, I'll be adding and changing tags as I go, M/M, My First AO3 Post, Other
Language: English
Status: In-Progress
Published: 2019-07-20
Updated: 2019-12-24
Packaged: 2020-07-09 00:08:12
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence, Major Character Death
Chapters: 6
Words: 56,961
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19878349
Author URL: https://archiveofourown.org/users/MKDremareRiser/pseuds/MKDremareRiser
Summary: After a mysterious kidnapping, Izuku finds himself with little memories of what had happened, and sets out to investigate. However, a chance encounter with the Number One Hero All Might and the mysterious vigilante, Kamen Rider, he finds himself entangled in a conspiracy bigger than he ever expected.





	1. Chapter 1

**Author's Note:**

> So this isn't my first foray into fanfiction (it is the first one I intend on keeping up with), but it is my first time using AO3, so that's fun. I always liked the Kamen Rider series since I was a kid, and My Hero Academia's one of my favorite manga/anime series. And I figured that Build (one of my all time favorites) and MHA would make for a great crossover.

It all started when a baby was born shining brightly in a hospital room. The first Quirk. At the time, chaos ruled the world, as more and more people began to manifest their Quirks, and the line between “human” and “non-human” blurred. Though thanks to the efforts of people who chose to use their newfound powers to protect others and governmental guidance, the world of Quirks entered the Age of Superheroes.

However, even the world of Quirks was not prepared for what would come in the future. 

* * *

“ _What are you doing? Let me go! Stop!”_  
  
_Izuku's screams fell on deaf ears, as he was shoved into a glass box with strange green liquid. He struggled against the grasp of the scientists in the white hazmat suits, who chained him down and fixed a mask over his mouth. He looked around frantically, seeing others chained to metal bed frames struggling and screaming like him. As a white gas began to fill the box, he spotted three strange armored figures that were a distance away, observing him, waiting._

_One was dressed in black with silver armor with pipes growing out of it, a yellow bat-shaped insignia resting on his chest, and the visor of its helmet matching it. The bat man was notable for being the only one in the tackiest chair that Izuku had ever seen (seriously, who gets a gold-leafed chair with velvet red cushions for a villain lab?). The second was dressed in red with gunmetal gray armor, its armor's pipes forming a muffler-like ring around its head. His insignia and helmet's visor were a green cobra instead. This cobra man was leaning against a pillar, as if this was just some sort of an everyday occurrence for him. And the third was dressed in gray, its black armor's pipes laying on its back like a jetpack, with a blue spanner forming its insignia and visor. The spanner man was just standing there, with his arms crossed, as if he waited for something. All three had strange, smokestack-like horns on the center of their foreheads._

_They were talking, though Izuku couldn't hear them clearly. In the middle of their conversation, the bat man noticed that he was looking at them, and let out a haunting laugh that echoed throughout the room, as the box was filled to the brim with the gas. It was the last thing he could hear before losing consciousness._

* * *

Izuku Midoriya bolted up from his bed, in a heavy sweat. “ _That dream again,_ ” he thought, wiping his brow. It had been days since he had gone missing and was found by the police and Mustafu's Guardian robot forces. The worst thing is how he couldn't remember anything, so he couldn't give any useful information about what happened to him. All he had was that dream, of that bat man, that cobra man, and that... spanner man. And honestly that wasn't too much to go on, so he kept that to himself.

His parents were just relieved that he was found, and he was allowed some time away from school to recover from his kidnapping and dumping. Today is the last of that break, so he got up to eat breakfast before getting ready.

As he walked out of his room and into the kitchen, he took a good look out the window, and sighed, seeing the mysterious red glow undulating over the Skywall.

The Skywall.

It had been ten years since it appeared, growing out of Japan's soil instantly. Izuku remembers watching the footage. It was the only other thing he would watch as a child besides All Might's debut. It all began as a celebration of Japan being the first country in the world to not only launch the first manned space mission since the rise of Quirks put a stop to any attempts at space exploration, but it was the first manned voyage to Mars. And there, among other strange artifacts, they found an odd metallic box that they chose to call the Pandora Box. An apt name, for when one of the astronauts interrupted the ceremony to slam his hand against the Pandora Box's top, it caused the Skywalls to rise up, shining its red glow on all those attending. No one knew why that astronaut did what he done, but the damage was too late, even with the arrival of nearby pro heroes to help save the people that were there.

It split Japan into three; Touto (where Izuku and his mother lived, since his father is working overseas), formed from eastern Honshu whose government practices pacifism and preaches for Japan to reunite as one, with only enough military strength for self-defense (it was thanks to this stance that Touto was in charge of keeping the Pandora Box safe at the Touto Institute of Advanced Matter Physics, since no one was willing to let it go to I-Island for testing after what happened). Seito, formed from western Honshu and Shikoku and Kyushu, focuses on economic recovery to stabilize itself due to the disruption caused by the Skywalls' formation. And Hokuto, formed from northern Honshu and Hokkaido, focuses on social welfare, as the Skywalls' formation also rendered its farmland infertile, forcing them to focus on introducing bills and programs to help its people in a time of need, though there are many conspiracy theorists claiming that Hokuto is working on secret military programs in order to take control of the other two countries.

Some say that the Skywall Incident was the worst event next to the sudden appearance of Quirks, though many debate whether or not if it's true. There have been many calls for the three countries to reunite, even All Might himself stated that Japan needs to stand together. But not even the Symbol of Peace has managed to convince the Prime Ministers of Hokuto and Seito to do so. For some reason, neither of them were willing to let one or the other “take control” of their country (some claim that direct exposure to that light must've scrambled their brains, since Prime Minister Himuro, who hadn't been able to attend the ceremony, is the only one who's for reunification).

Izuku's mind didn't linger on this topic for too long, since by now the Skywall's presence had become simply an everyday thing for him. What really mattered right now was his kidnapping, and what happened to him during the time he went missing.

“What happened?” Izuku muttered, as he poured out cereal into a bowl. “Why can't I remember anything during my kidnapping? Did some sort of memory erasing Quirk get to me? Is it related to that dream? Or-”

Izuku muttered and muttered as he ate his cereal, trying to piece together what happened. All he remembered was leaving school after a long day of dealing with Bakugo and his friends' bullying, walking under the bridge on a route he rarely took, and then the next thing he knew, he's in some torn up clothes laying in some abandoned warehouse where they found him, miles away from school. For the most part, he couldn't really come up with a good motive for his kidnapping, since he was Quirkless, and came from a middle class household. Or was it precisely because of his Quirklessness was what caused them to kidnap him?

Whatever the answer is, it must have something to do with that dream, since it must be some sort of suppressed memory of some sort. If only he could get more information out of it. Then he could truly begin to investigate what happened. He looked at the clock, and realized that he needs to get going soon. Maybe going to that bridge after school again will give him some answers.

* * *

The morning commute isn't so bad this time around, since he got to watch some heroes take down a criminal, though Mt. Lady definitely took the spotlight away from Kamui Woods. But going to school immediately ruined his day. Class was also pretty uneventful, since Izuku kept quiet, and it seemed like his classmates, despite looking like they have a lot of questions, didn't want to approach him. Whether or not that was because they had sympathy for him being kidnapped or were freaked out that he's back, it wasn't clear.

“Hey, did you hear about the rumors?” one of his classmates said, during lunch. Izuku was in the back eating his lunch quietly, but he couldn't help but overhear what they were talking about.

“About what?”

“About the Kamen Rider!”

“You mean that weird vigilante? He's just an urban legend!”

“Nah man, my brother got a friend who's got a cousin whose boss's best friend's former classmate was saved by the Kamen Rider! He fought this guy who's Quirk went haywire and saved him!”

“I don't get it, what's so special about that?”

“Well, after he beat that guy up, he used this weird bottle thing, and it turned him back to normal!”

“Really? A bottle? That sounds stupid.”  
  
“Hey, I'm just saying what I heard!”

The Kamen Rider. Izuku's seen the rumors online, of a red and blue armored vigilante who's been going around and helping people from others whose Quirks went out of control. Thing is, no one's ever gotten photographic evidence, and heroes who've been on patrol have stated that they've never seen someone like that. Even some vigilantes stated that they haven't seen him. And that's not even going into how the Kamen Rider makes his gear, since it's all probably pretty pricey if the rumors were right about him using a motorcycle and some sort of weird drill-sword-gun contraption are true. As lunch ended, their homeroom teacher entered the classroom with a stack of papers.  
  
“Alright, settle down, everyone!” he stated, as everyone returned to their seats. “Now, I know I'm supposed to be handing these career forms for you all to fill out today,” he added, motioning to the papers he had just put on the desk. He grabbed them, and took a good look at the class for a second, before just tossing them into the air. “But why bother, you all want to be heroes, right!?”

The class erupted into cheers, as Izuku's classmates started activating and showing off their Quirks. 

“Yes, you all have wonderful Quirks, but remember, we're in school! No using them in public! Please remember the school rules, everyone!”

As the cheering died down, there was a scoff near the back of the room. Izuku looked to his side, and saw his childhood friend, Katsuki Bakugo, smirking smugly. Izuku grimaced, and prepared for the incoming tirade. 

“Hey teach! Don't lump me with the rest of these losers!” he shouted. “We all know that I'm the only one with a Quirk that isn't total garbage!

“Shut up, Bakugo! You're not that great!” one of them yelled, as others muttered in agreement.

“Well, since Bakugo's making himself the center of attention, I guess I'll mention that he's planning on applying to U.A.,” the teacher said, to the astonishment of their classmates. “U.A.!?”

“That's the toughest Hero school in Touto!”  
  
“Only the best of the best get in!”

“That's right, I'm in a different league than all of you extras!” Bakugo shouted, as he jumped onto the top of his desk. “I already aced the mock exam, so the real thing will be a piece of cake! I'm gonna get into U.A., then I'm gonna be the best Hero there is! No one, not even All Might himself can top me! Hell, I bet I could even break down that stupid Skywall no problem!”

“Oh, now that I think about it, the only other person who mentioned attending U.A. too is Midoriya...” the teacher said, trailing off a bit as he looked at Izuku. All eyes went onto him. Izuku's heart stopped beating as people began muttering.  
  
“Really? Midoriya wants to go?”  
  
“Probably not anymore, since he got kidnapped and all.”  
  
“Yea, he'd pass out at the written exam alone after that.”  
  
He didn't like this. He was just getting by the entire day without causing a scene, and now everyone was paying attention to him. All he wanted was to get school over with so he could start investigating what happened to him at that bridge.

“Deku!” Bakugo cried, jumping off his desk to slam his hands onto Izuku's, making it explode a bit thanks to his nitroglycerin sweat. “You really think you could make it into U.A. without a Quirk!? There's no possible way they'd let you in like that!”  
  
“W-well they did start letting Quirkless students enter, so I don't-”  
  
“Give it up, Deku! You're too weak! You couldn't even protect yourself from being kidnapped, you idiot!”  
  
“Alright Bakugo, that's enough,” the teacher said sternly, as Bakugo returned to his seat, glowering.

Izuku spent the rest of the class tense, as he wrote down notes and listened to the teacher, while jotting down questions and theories he had about his kidnapping in between, even drawing down the villains down as best he could. During it all, he'd take quick peeks at Bakugo, and sighed. He really wished their relationship hadn't turned into this. He and Bakugo used to be very close as children, but when it turned out that Bakugo had a Quirk and he didn't, their friendship turned sour. Nowadays Bakugo just looks at him with nothing but contempt, though Izuku genuinely still respected him. He wished that they could just go back to the days where they talked about heroes like All Might, go on expeditions and adventures through the woods, anything, honestly.

At the end of the school day, Izuku sighed and started packing up his books when one of his hero journals slipped and fell to the ground. Before he could pick it up, Bakugo snatched it.

“What's this? 'Hero Journal No. 13'? Come on, you're still writing this crap down?”  
  
“G-give it back, Kacchan!”

“Or what? Gonna fight me?” Bakugo said, as he moved his hands to clap onto Izuku's journal to make it explode. “How you gonna do it? You-”

It all happened in a flash. Izuku leaped up from his desk, and gave Bakugo the hardest shove he could muster. To everyone's surprise, Bakugo was knocked off his feet, sending him flying into the desks behind him. In shock, Bakugo had released his grip on the journal, which fell towards Izuku's feet.

Everyone was frozen. No one had ever seen Izuku retaliate against Bakugo like that, let alone have such sudden monstrous strength. Izuku stood there, paralyzed with fear at the sudden realization at what he had done, staring at his former friend and the giant pile of desks he was laying in. Bakugo was paralyzed as well, though that was immediately replaced with a seething, unrelenting fury.

“ **DEEEEEKUUUU!** ” Bakugo screamed, his brow furrowed as sparks started to fly from his palms as he got up. Izuku didn't wait for Bakugo to keep talking, though. He swiped his journal off the ground, shoved it into his bag as quick as he could, and ran off, faster than anyone had ever seen him go.  
  
“What the heck happened!?” he thought, passing by stunned student after stunned student. “How did I get so strong!? And fast!? What's going on!?”

As he began mumbling to himself, he grew more and more frustrated. He needed answers. He _wanted_ answers. And if there's any place to start that, it'd be at that bridge again. "Out of my way, please!" he said, as he dodged people to make his way out.

* * *

“Out of my way, bastards!” a sludge-like man cried, rushing past person after person, his tentacle-like “arms” full of cash registers. One unfortunate man, an unassuming fellow with short black hair dressed in a striped t-shirt, jeans, and a large brown overcoat, was slapped to the side by one of his tendrils. “Move or I'll kill you!”  
  
“Ow! Geez, what a jerk,” the man said, rubbing his head. “Could've knocked my brain loose, and I need that.”

“Don't worry citizen,” a deep voice said behind him, as a large hand grasped his shoulder. The man looked back, and gasped, as he saw a large, intimidating blonde man standing near him. A man that anyone with a quarter of the size of his brain could recognize. “For I am here!”

The blonde man broke into a run after the sludge man, whose bulging eyes bulged out even further, leaving the man in the overcoat behind in the dust. “Holy crap... He's a lot bigger than I expected,” he muttered, scratching his head. But something was a little off about him. How did he not notice him standing behind him like that? He was certain that when he was passing by that convenience store, that there wasn't anyone there that looked like him. As he began to grind the gears in his brain, a tuft of hair stuck out, before he patted it down.  
  
“What am I doing!? I can't think about this now! I gotta get to the Institute for work!” he said, shaking his head. He looked around, making sure no one could see him, and he slunk into a nearby alleyway. The man pulled out a strangely-shaped cellphone, along with a small, equally strangely-shaped bottle from his pockets.

He inserted the bottle into a slot that was attacked to the back of the phone, and almost immediately, it grew in size, folding and unfolding itself until it changed into a motorcycle. He climbed onto the motorcycle, and pressed onto its screen, making it materialize a helmet that he put on his head.  
  
“Well, can't let them wait for the _genius_ scientist for too much longer, right?” he smugly stated himself, revving the engine and drove out of the alleyway.

* * *

Izuku had made it to the bridge quicker than he anticipated, in no part due to having just ran as fast as he possibly could to avoid Bakugo's explosive fury. He sighed. He respected Bakugo, with all of his heart. While... very abrasive, Bakugo's drive to become a hero was second to none. Not to mention that he really was one of the toughest guys that Izuku knew. He didn't mean to shove him so hard like that, and in front of so many of their classmates. No wonder he wanted to beat him up so bad.

Still, at least he could be consoled with the fact that he saved one of his Hero Journals, as he flipped through the pages. Admittedly, it wasn't nearly as full as he would've liked, mostly in part that he had missed a few days' worth of work in it thanks to his kidnapping (quite frankly he was amazed at the fact that his bag wasn't lost forever and that some kind soul returned it to his mother), but he wasn't about to let that deter him from resuming his observations, though now some of the pages were instead full of questions and theories about what happened. Some of which now involve his sudden increased strength and speed. How did that happen? When did that happen? How much of that dream was real? Were those really his kidnappers in his dream? And what did they do to him?

He began to scan the underpass of the bridge. He touched every crack on the wall, observed every pebble on the ground. Anything could be a clue about his kidnapping, anything at all. His eyes were glued to the walls and ceiling, so it was unfortunate that he didn't take the time to look at the manhole that was behind him.

“What am I looking for?” he muttered to himself, as strange sludge-like liquid began to ooze out from the holes and cracks of the manhole. “They couldn't have knocked me out with a chemical. They already checked for that... Maybe some sort of sleeping powder like Midnight? But there's no powder around... Maybe-”  
  
“Thanks for the meatsuit, kid!” the sludge said. Izuku finally whipped around, and as soon as he did, the sludge man enveloped him, shoving himself into his mouth. “Don't bother struggling, it'll all be over soon!”  
  
Crap, it's happening again. Another villain's taking him hostage. He can't believe it. Is this underpass just cursed for him? Definitely never going anywhere near it again, if that's the case. If there's ever an “again” for him, at least.

It wasn't fair. None of this was. Being born Quirkless, losing his friendships, and getting kidnapped, twice? He didn't know what happened for him to deserve this, but it wasn't right. The indignity of it all infuriated him. He struggled and struggled, as he futilely tried to pull the sludge man out of his throat. But it was getting him nowhere. With one, final attempt, he tried to give the sludge man one good, defiant slug to his eye. Surprisingly, he didn't miss, and in fact, forced a good scream out of him.  
  
“Ow! Lucky punk! You're a lot tougher than I thought!” he grumbled, recoiling back a bit from the sudden pain in his eye. “But it's too late! I'm nearly finished, and I'll-”  
  
“You'll what!?” a voice yelled, coming from the manhole. It was a familiar voice. Izuku had heard it thousands of times. But it couldn't be.

The manhole cover flew off, embedding itself into the ceiling above it. A large, muscular, blonde man with rabbit ear-like bangs jumped out of the sewer. “You'll do nothing, because _I AM HERE_!”

It was.  
  
The Number One Hero. All Might. Though he wasn't dressed in his hero garb, just a plain white t-shirt and green pants. He was probably out shopping or something while off the clock.

“Shitshitshitshit!” the sludge man cried, raising his tendrils. But before he could do anything, All Might reared his mighty fist, before letting out a mighty cry. “ _TEXAS SMAAAAAASH!!!_ ”

All Might punched the air in front of the sludge man, creating a gust of wind so powerful that he was being ripped apart by it. The sludge man struggled to keep his hold onto Izuku, but it was too much. With a cry of frustration, the sludge man dispersed into muddy puddles, too weakened by the attack to pull himself together. Izuku fell onto the ground, hard, as he moaned from the pain of it all.

The Number One Hero rushed to Izuku's side, picking him up and helping him on his feet. “Are you alright, my boy?” he asked, his deep voice gentle. “It was a good thing I made it in time.”  
  
“N-n-no worries, I'm fine,” Izuku said, pulling up a smile, before immediately retching out the pieces of the sludge man that were still in his body. Plus whatever he had eaten that day. “I-I-I'm serious, totally fine.”  
  
“You're totally not! Here, drink this,” All Might said, as he pulled out a couple of bottles from his pockets. “It's ginger ale, one of my favorite brands. Drink as much as you like.”

Since it was being offered to him by his idol, Izuku gladly took one of the bottles and quickly downed it, stopping in between gulps to take a deep breath. “T-thank you for saving me, All Might! I-I-I-” he stuttered, as he handed the empty bottle back to All Might.

“Don't mention, my boy! After all, it is a hero's duty to save citizens!” All Might replied, ending his sentence with a hearty laugh. “Though I do wonder how I'll take this criminal back to the police...” he said under his breath, before looking at the empty bottle in his hand. “Ah! I'll just use this to store him! Thank you for your help, young man!”  
  
“A-a-anytime, All Might!” Izuku said, as he bowed up and down nonstop while All Might scooped up as much of the sludge man as he could into the empty bottles. “W-w-will you please sign this for me!? I'm Izuku Midoriya, I'm one of your biggest fans, and I-”  
  
“No problem! After all, you did just go through a perilous situation!” All Might said, grinning. As he flipped through the pages to find an empty spot, he saw all the notes Izuku had made in that journal. So many observations and ideas about heroism. It was quite inspirational, really. To think that someone like this could earnestly love heroes so much. But it was the last few pages where he stopped and really read through them.

They were questions, theories, and ideas, but not about heroes. They were instead about a kidnapping. His kidnapping.

“My boy,” All Might said, his voice becoming soft. “Where you the one that had gone missing a few weeks ago?”

Izuku's nervous smile faded away, and replaced with a much sadder one. “Y-yea,” he admitted, rubbing the back of his head. “I was thinking that if I came back to this bridge to look for some clues myself, I'd find them, but I guess this place just has it out for me, huh?”  
  
“My boy,” All Might said, putting a gentle but firm grasp on Izuku's shoulders. “It'll be alright. I'm sorry that I wasn't here to help you in your time of need before, but I am certainly glad that I was here this time.”  
  
Izuku gasped as he heard All Might's words. In all of the interviews and shows All Might has done, he's never quite heard this sort of tone from him before. Usually he was loud and boisterous, as if he were challenging all those who'd cause chaos and pain to face him. But here? It was so reassuring, gentle, and kind. If he was speaking like that, maybe he could-

“I'm truly sorry that I couldn't help you before,” All Might said, snapping Izuku back to reality as he handed him back his journal, complete with his signature. “But I assure you, you'll be fine now. For now, I have to take this criminal to the authorities. Take care, my boy!”

As All Might prepared to make a mighty jump to take the criminal elsewhere, Izuku's heart sank. He had so many more questions, so many things he needed to tell All Might. His quest for answers about the kidnapping can wait for a bit, right now there was a once-in-a-lifetime chance, and he needed to take it. So without thinking, he latched onto All Might's leg, right before he jumped.

“Whoa whoa whoa! My boy, I understand that you're a big fan and that you've got many things to say to me, but this is a bit too much, even for me!” All Might said with an unflappable grin, looking down at his legs. “What are you thinking!?”

“I-I have so many things to ask you, to tell you! It's so much more than just what happened and that kidnapping! I-it's really important to me!” Izuku said, as the wind blew onto his face and through his hair. “Plus, if I let go right now, I'll fall to my doom!”  
  
“Alright, I'll land on a rooftop and answer one more question, but that'll be it! I really do have to hurry!” All Might said, shaking his head. He really couldn't believe this; oh well, the things that fanboys will do, right? Though he couldn't linger on that thought too long, as a small trickle of blood started to flow down his cheek from his mouth.

* * *

“So did you catch Mii-tan's newest podcast? That was a pretty good segment,” one of Bakugo's classmates said, as they walked into an alleyway. “Never thought I'd seriously consider about what would happen if you'd pit a turtle against a rabbit.”  
  
“Pffft, yea, that was pretty funny, though I've been just waiting for her to release a new song. She's a fantastic singer, not to mention super cute,” another one said, looking down at his phone, watching said idol sing and dance. “What did you think about it, Bakugo?”

“Dammit, what the _fuck_ happened back there!?” Bakugo muttered, ignoring their prattle as he practically ground his molars to dust. He kicked a bottle out of his way. “When the _fuck_ did Deku get so damn strong!?”

He hated this. He hated everything about this. Ever since they were kids, Izuku had dreams that were far too big for him to have. What kind of helpless insect like him could ever think he could amount to anything? The bastard was a liability, no one would want a hero who couldn't help themselves like that. Especially if that hero was someone who got kidnapped just weeks ago.

“Yea, he got you pretty good with that shove,” one of them replied, as he started to light a cigarette up. “Didn't know he had it in him.”  
  
“Not in him enough,” the other snickered. “Dude practically pissed his pants after what he did.”

“Yea, who knows? Maybe he will end up going to U.A., too.”  
  
“Shut it!” Bakugo growled, as a small explosion went off in his hands. “And stop smoking! If anyone catches when I'm around, it'll go on my record too, dumbass!”  
  
Before anyone could say anything else, a huge shadow loomed over Bakugo. He turned around, and saw a giant sludge man staring down at him.  
  
“Now that's a nice Quirk!” he laughed. “Mind if I take your body!?”

* * *

“Seriously, that was a very reckless thing to do,” All Might said, chastising Izuku while he was catching his breath from his impromptu ride. “So, what is the question you need to ask me? It needs to be fast, and I-”

“Yes, um, I was thinking!” Izuku yelled, as he struggled to find the words he needed to say. It was hard to dig them out, to say the least. He had always thought about what he needed to say to All Might, though with recent events he nearly forgot about them. But right here, right now, he's going to take care of that weight that has been on his chest ever since he was four. Ever since he learned about his Quirklessness.

“C-can I become a hero, even without a Quirk!? All my life, I wanted to become a hero, just like you! Someone who could bring smiles to everyone he sees, that can protect everyone's peace, and who's fearless in the face of danger. But I... I was unlucky enough to be born without a Quirk. So, d-do you think, I could become a hero!?”

All Might took pause at what Izuku said. Something about those words seemed to resonate with him, as he thought deeply and considered the words that Izuku had said. Just before a big cloud of steam enveloped him. “Shit, I'm close to my limit!”  
  
“A-All Might, are you alriIIIIIIIGHT!?” Izuku cried, as he looked on at his idol hero. When the steam cleared, where once stood a muscular giant of a man, now stood a man, almost skeletal in appearance, with straggly hair and clothes far too big for his body, his eyes were covered with shadows, with bags sagging underneath. “W-who are you!? What did you do with All Might!?”

The man looked at Izuku, his face nearly unreadable. “I am All Might,” he said, as a small waterfall of blood trickled out of his mouth, freaking Izuku out. “Okay, um, you know how there are guys at pools who'll suck in their gut to look more buff? That's what I do, sort of.”  
  
“Seriously!?” Izuku said, still processing what was going on. All Might shook his head and sighed, clearly disappointed at having his secret revealed. “All right, I'll let you in on a secret, but this better stay between us, is that clear? Only a few people know about my condition, and I can't let others see me like this or hear about it.”

All Might pulled up his shirt, and what Izuku saw made him want to vomit all over again. All Might's abdomen was a mess of stitches and scar tissue, discolored and disfigured from what appeared to be from multiple surgeries. “About five years ago, I got into a big battle with a powerful villain who gave me this wound. Lost parts of my stomach, a lung, basically my respiratory and digestive systems are pretty much shot. The amount of surgeries I had to get and their aftereffects basically caused my body to waste away, to the point where I'm only really able to work for three hours a day.”  
  
“No way... Wait, was it the fight against the Toxic Chainsaw?”

“Heh, you sure know your stuff. Nah, as if that punk could do anything to me. The guy who did was in a league of his own, and the only reason why I got away with my life, was because I managed to hit him as hard as he hit me.”

“So is he-”  
  
“Hopefully. That's the sad truth, young man,” All Might said, wistfully. “Sometimes, to stop a villain, you gotta go all out, no holding back. Otherwise too many people would get hurt. But some good doing that did.”  
  
“What are you talking about, All Might? You're the Number One Hero! You're the Symbol of Peace, wherever you go, people feel-” Izuku said, only to be interrupted by All Might's harsh laugh. It was nothing like the boisterous laughter he was famous for, but one of bitterness and pain.

“'Number One Hero'? 'The Symbol of Peace'? Haven't heard that particular one for some time, thanks to that,” he muttered, pointing to the Skywall and its ever present red glow. “Even before I took out that villain, the Skywall tore down everything I worked for up to that point. You know what they call me over at the other sides? 'The Symbol of Touto', 'Touto's Mightiest Hero', 'Touto's Peace', Touto this, Touto that. I tried getting permits that allowed me to work in Seito and Hokuto too, but I kept getting turned down. And for all that fame and presence I had, I couldn't get the Prime Ministers or any government officials to agree to unite into one country again. In the end, all I got to show for my efforts are three broken countries, and this wound that'll never truly go away.”  
  
“But even still, a Symbol of Peace, or anything of the sort, who saves people with a smile, can never be daunted by the likes of evil. The reason I smile nowadays is so I can push back against the fear and pressure I feel as a hero, especially with that wall hanging around. Pro heroes have to put everything on the line, and being Quirkless? I don't think it's possible.”

Izuku slumped to the floor. That spark of hope he had about achieving his dreams vanished into thin air once again. He clutched his heart, which threatened to burst out of his rib cage as despair began to overcome him. At least, until he remembered what happened earlier that day.

“Wait... what if I told you that I did get a Quirk? At least, recently?”  
  
“... Come again?”  
  
“Y-yea... come to think of it, ever since I got kidnapped, I had been feeling weird... it didn't occur to me until today, after I accidentally knocked a classmate into some desks... But I've suddenly gotten super strong and super fast... Maybe... Maybe something that my kidnappers did gave me a Quirk! If I got-”  
  
In the middle of speaking, Izuku noticed All Might's face. His expression became grimmer, as if he saw some sort of ghost. His fists trembled, as if something about what Izuku said terrified him.  
  
“Young man,” All Might finally said, struggling to push out the words from his mouth. “Did you happen to have a good look at your kidnappers? What did they look like?”  
  
Izuku was taken back. This situation kept swerving in and out of so many places at once, it was difficult to really keep up. “W-well, honestly, the most I've got is this dream. I think it's related to my kidnapping, but well... There were these weird scientists in white hazmat suits, and I saw their bosses, I think... One was dressed like a bat, another like a cobra... And the third one was like, dressed as a spanner? I don't get the last one, but that's who were in my dream... Wait, do you think you know my kidnappers?”

All Might sighed, both out of relief, and disappointment. “Sorry, my boy, I was worried for a second that I knew who had taken you, but the people you described? I'm not familiar with them. I do remember seeing your drawings of them though while flipping through your journal. That's a decent lead, so I'll keep an eye out for them.”  
  
All Might gave Izuku a reassuring pat on the shoulder, shaking his head. “Well, in any case, I feel like there's a lot for you to think about. Just be aware that whatever those villains did to you, it might not be permanent. But for now, I have to get going. Take care, young man.”  
  
As All Might climbed down the stairs, Izuku stayed on the floor, as he tried to hold back tears. This day had been the worst roller coaster of his life. For one moment, he thought that All Might could've told him he could do it, become a hero. That it'd be a matter of just putting his all into it. But the best of the best said it himself. Without a Quirk, he couldn't be a hero. And like All Might said, this sudden burst of strength and speed? It might not even be permanent, so he can't rely on that power. When he heard the stairway door click, a torrent of tears flowed down his face.

This day couldn't possibly get any worse.

* * *

All Might's day got worse the minute he stepped out of the building

“Alright, now to get this guy to Tsukauchi and-” he said to himself, checking his empty pockets. He froze. His empty pockets. Before he could say anything else, he saw an explosion go off a few blocks away, as horror crept onto him.  
  
“No...,” he muttered, as he rushed down the street. Despite losing much of his strength and power in his thin form, he was still quite a good runner. One that was missing a lung, mind you. So it was no surprise that by the time he made it to the area of the explosion, he was out of breath.

The scene was unbearable. The captured sludge man had gotten out of his confinement, and now had some other kid as a hostage, using what he assumed was the boy's Quirk to make explosions. Fires were everywhere, the road was torn apart, broken Guardians laid near the sludge man's feet, and pro heroes were doing everything else but stopping the sludge man.

“Sorry, but my wood Quirk's useless against this guy! I'll keep the civilians out!” All Might recognized that hero, he was that newcomer, Kamui Woods. He was carrying as many civilians in the branches coming out of his arms as he rushed out of the area.

“This is a single lane street! I'm too big for this!” That was another newcomer, Mt. Lady. All Might saw her struggling to get past two buildings, but like she said, she was too large to get through.

“These fires can't put themselves out! I'll take care of these until the firemen arrive!” Backdraft, a firefighter-esque hero, said, as he doused the flames the sludge man was making with his explosions.  
  
“Dammit, none of our Quirks work against this guy! If only I had one that was strong enough to blow him away!” Death Arms, a muscular man whose gear was painted like construction vehicles, said, clutching his fist tightly as the sludge man rampaged with wild abandon.

All Might grasped at his aching scars on his chest. He should've been more vigilant. He was careless. It was all his fault. He couldn't bring himself to blame poor Midoriya, he didn't mean to take up any of his time like that. He had been going through so much, and he already felt bad enough about ruining his dreams of being a hero.

“Dammit, what can I do!?”

* * *

Izuku sighed as he walked down the streets after he finally calmed down long enough to go downstairs. He couldn't blame All Might for what he said. It was time that he accepted the truth that's always been in his face. There was no heroic career paths for someone without a Quirk like him.

There was a time where he entertained the thought of becoming a Quirkless hero, but after he plugged in the numbers of how much money he'd need for equipment, maintenance for said equipment, and healthcare in the case that he'd get injured in fights (which would probably be often, considering how it'd be stacked against him), he realized that the only way that was happening was to suddenly become a billionaire with incredible disposable welfare. So that was definitely out of the question for a kid with a stay-at-home mother and a father working overseas.

As he absentmindedly walked down the street, he saw a big commotion on the other side. “Oh, a villain attack. I guess I'll go see it.... What am I even doing anymore? I'm Quirkless, I got kidnapped, possibly experimented on, and my idol told me that I couldn't be a hero without a Quirk. I should just move on-”

Izuku froze when he finally saw the villain. It was the sludge man from before. The bottle containing him must've dropped out of All Might's pocket when he latched onto his leg. And he had a hostage too, just like what he did to Izuku. A hostage who had a very familiar explosive Quirk.

“Kacchan!? Oh no, he got him! This is all my fault!” he thought, as people muttered about where All Might could be, since he had been seen chasing the sludge man earlier. “If I hadn't grabbed his leg when he jumped, he wouldn't have lost him! And I wasted his remaining time, too! Don't worry, someone will come to stop him. Someone will come to save Kacchan-”

For the briefest moment, Izuku and Bakugo locked eyes with each other. And in that brief moment, Izuku saw the terror and pain in Bakugo's eyes.

His feet sprung to action, as he leaped out of the crowd towards his former friend, stunning everyone present, heroes included.

“What's that kid doing!?” Death Arms cried out, as the heroes start rushing forward, though Izuku's speed was unprecedentedly fast. “He's gonna get himself killed!”

“Him again!?” the sludge man muttered, scowling as he prepared to let out some more explosions. Bakugo could only let out a garbled “Deku!?” as he saw him running towards him.

“What am I doing!?” Izuku thought, as he rushed forward. “What should I do!?”

As he thought back to when the sludge man had him, he remembered that he had smacked him in the eye and he temporarily lost some control from the strike. So he took his backpack off, and tossed it right into the sludge man's face. The impact struck him right in the eye, and as he screamed, he recoiled, allowing Bakugo some time to breath, right as Izuku landed onto them and desperately clawed at the sludge covering him.

“What the hell do you think you're doing!?” he growled, as Izuku kept clawing and clawing. “I don't need your help!”  
  
“I'm sorry!” Izuku replied, as tears streamed down his face. Air kept moving in and out of his lungs, his heart beating 80 miles per second. His arms trembled, but he kept going. “B-b-but when I saw your eyes, all I could think of... was how scared you were, and I needed to help!”  
  
“Stoooop!” Bakugo screamed, as he began to recede back into the sludge man.

“Stupid bastard, die!” the sludge man cried out, regaining his composure, and to release one more explosion. If it weren't for the fact that All Might's large hand grabbed both Bakugo's and Izuku's hands.

“How foolish of me, to not practice what I preach,” he said, as everyone laid eyes onto him. “And to think, I had chastised you about this earlier today. What good is a hero, who doesn't put everything on the line!?”  
  
He pulled Bakugo and Izuku free from the sludge man, and with his free hand, raised it to the skies, and let out a mighty cry.

“ **DETRIOT** _ **SMAAAAAAAASH!!!!!**_ ”

He slammed his hand to the ground, the air around him bursting so hard and fast that the sludge man scattered everywhere, letting out one final scream before losing consciousness. The clouds gathered, as rain began to pour down on the city.

“I can't believe it! The air pressure from his punch changed the weather!”  
  
“That's the Number One Hero of Touto for you!”

“Man, what I wouldn't give to get a super strong Quirk like that!”

Izuku sat on the ground, looking up at All Might. Despite what had happened earlier today, All Might really pulled through. While this would've been relieving, he knew that if it weren't for him, this whole situation wouldn't have happened in the first place. He sighed, and laid down on the ground, tired beyond belief.

* * *

It took a while, but the heroes managed to gather every single droplet of the sludge man from the ground and buildings in large trash bags, handing over it all to the police. And as expected, Izuku was being reprimanded for his recklessness, while Bakugo was being praised for his bravery and strength.  
  
“That was a dangerous thing you did, kid! There's a reason that you have to let pro heroes save people!”  
  
“Wow boy, you've got one strong Quirk! When you graduate, come to my agency, we'll take you on as a sidekick, no doubt about it!”

Izuku couldn't blame them, what he did was a pretty idiotic move on his part. Still, he had to do something, he couldn't just let Bakugo suffer like that. But before they could keep scolding him, the air of chatter of bystanders and reporters fell silent when a gunshot echoed. Everyone stood still, looking for the source, when a strange gaseous bullet flew through the air. It weaved in and out of the crowd, dodging every single person as it made its way to its target.

Bakugo.

“Kacchan!” Izuku cried, seeing the bullet hit Bakugo squarely in the chest. Instead of metal shrapnel, the bullet exploded into a cloud of gas, enveloping Bakugo.

“The hell is this shit!?” he cried out, as he swung his arms wildly. “Get it off me! Get it off-”  
  
Bakugo's voice became a low growl, and the cloud dissipated. Where the spiky ash-blond boy once stood, was now a being unlike anyone has ever seen. The gas had turned Bakugo into some strange robotic-like creature. From head to toe, his flesh had turned into a strange metallic armor-like skin, his fingers now had blowtorch-like openings on the tips, his palms each having a strange exhaust ports. His head was now shaped like a strange airplane cockpit-like helmet, his chest had four odd small openings, and some sort of jetpack was now resting on his back.

No one, not even mutant-type Quirks, had ever looked as strange as this.

As quickly as he transformed, Bakugo started rampaging, setting explosions one after another, running into the panicking crowd. “What the hell happened!?” Death Arms said, as he and the other heroes rushed in to restrain the now-monstrous Bakugo. “Is this some new form of Trigger!?”  
  
“I've never heard about Trigger transformations being this drastic!” a caped hero said, struggling to hold back one of Bakugo's arms. Bakugo let out a monstrous cry, and to everyone's shock, small missiles started to fly out of the holes in his chest. “Especially one that give people entirely new abilities!”

Bakugo swung the heroes off of him, before firing off more explosions onto them, knocking them to their feet. All Might leaped over the crowd of reporters, and caught Bakugo in a tight bear hug.

“My boy, stop this madness! I know you're better than this!” he said, as Bakugo struggled within his grasp, before letting off another powerful explosion into All Might's left side. He cringed, and in the split second he went to hold his pained wound, Bakugo freed himself, setting off more explosions and firing more small missiles.

“Kacchan, please, stop!” Izuku pleaded, as he stepped towards the rampaging boy. “All Might's right, you are better than this! Out of everyone I've ever met, you've never backed down! You always stood your ground! This isn't you! So please, calm down so we can figure out what's going on!”

Bakugo froze, as if he was considering what Izuku said, before immediately raising his hand. Before he could let out an explosion right into Izuku's face, a man jumped from one of the buildings, kicking Bakugo right in the face. After landing on the ground, the man stood up, letting all those around have a good look at who he was.

The man was wearing strange armor that was divided into red and blue diagonal stripes, with his undersuit being black with similar diagonal lines. On the top of the left of his chest armor rested a red triangular bar with a blue tank-like barrel underneath it. His right arm was red, while his left arm was blue; whereas it was the opposite for his legs. His right foot appeared to have a tank thread of sorts, while a white spring-like structure covered his left shin. On his waist was a yellow belt with a strange black device with a hand crank, with a pair of bottles inserted in it, one red and shaped like a rabbit, the other blue and shaped like a tank. What was very peculiar was his helmet. Instead of a regular visor, his helmet has eyes. Mismatched eyes. His right eye was shaped like a blue tank, while his left eye was shaped like a red rabbit's head.

There was no doubt about it. This was the Kamen Rider.

“Thanks for keeping him occupied, but I'll take care of the rest from here,” the Kamen Rider said, his voice clearly modulated to hide his identity. The Kamen Rider dusted his hands off, before a set of tubes moved out of his belt to create (or summon?) a strange weapon that appeared to be a sword, drill, and gun all at once. “Time for my public debut!”

Bakugo charged towards the Kamen Rider, small explosions going off in his hands. The Kamen Rider, undeterred by this, simply raised his weapon above his head, the blade spinning, and brought it down onto Bakugo, causing sparks to fly.

“Stop! Don't hurt him!” Izuku cried, as Bakugo staggered back. “Something's wrong with him, that gas bullet-”  
  
“Don't worry, I know what's going on. I'll get him back to normal,” the Kamen Rider said, as he followed up with a punch. “Thing is, I gotta weaken him first by fighting him, otherwise I can't.”  
  
Bakugo growled, and a volley of missiles began to fly out of his chest. The Kamen Rider dodged each of them, though the last one managed to knock him off his feet.

“Oof, that one was a bit tough. Hm, let's try out this,” he said, pulling out the bottles from his belt. He switched the red bottle for a green turtle-shaped one, giving them a little shake before twisting the caps open, and inserted them into the belt. What surprised Izuku was that the belt spoke.

“ **Turtle! Tank! Are you ready?** ”  
  
The Kamen Rider grasped the hand crank on his belt device, and started to rotate it, strange music playing out of his belt. When he finished, he announced, “Build up!”, and the red of his armor was replaced with green. His left eye was now shaped like a turtle, and a large turtle shell-like shield was now on top of his shoulder. Bakugo roared again, and launched another series of missiles. The Kamen Rider stood there, but before any of them landed on him, he moved his right hand, and a shell-like energy barrier formed in front of it, absorbing all of the explosions.  
  
“Hm, this barrier ability is good, but it definitely needs the Best Match to really make it shine,” the Kamen Rider muttered to himself, as Bakugo made for another charge. He curled his left hand into a fist, blue energy filling it, before letting it out in one powerful punch. “Tank's power is a bit weaker, too. And I feel way too heavy with this big shell on my right arm. I guess RabbitTank is the winning formula, after all.”

He pulled out the bottles again, and swapped the green one for the red one once more. He shook the bottles again, though this time, strange giant science and math equations started to float from behind him, pushing Bakugo back. After twisting the caps once again, he inserted them back into his belt and cranked it, but the belt's announcement this time was unique. And instead of the colors simply swapping, tubes formed from the belt, turning into runners that formed the Kamen Rider's armor.

“ **Rabbit! Tank! Best Match! Are you ready?! The Moonsault of Steel! RabbitTank! Yeahhh!** ”

The runners slammed onto him, the green on his armor turning red once more. He held his weapon once more, but he pulled the blade off, and reinserted it into the handle, turning it into a gun. The Kamen Rider pulled out another bottle, this time a white one shaped like a refrigerator, and inserted it into his weapon, which, like his belt, made an announcement.

“ **Ready go! Vortex Break!** ”  
  
He pointed his gun at Bakugo, and fired a stream of cold air. When it made contact with him, ice began to form over him, immobilizing him in place. Once Bakugo was completely frozen, the Kamen Rider began to crank his belt once more, though this time for much longer.

“One moment, please,” he said, before running off in the opposite direction, much to everyone's shock.

“You bastard! Get back here!” Death Arms cried out, right before the Kamen Rider jumped up a bit before landing and falling into a hole. Before anyone could process what was happening, a pillar shot out of the ground where the Kamen Rider was, with him on top.

“ **Ready, go! Vortex Finish!** ”

And a giant sloping graph formed, pinning Bakugo in it and shattering the ice he was stuck in. The Kamen Rider leaped off the pillar, and slid down the graph, gaining more and more speed before landing a powerful kick on Bakugo, causing him to explode.

Bakugo was sent flying back, landing hard onto the ground. But he was too weak to get back up, as any attempt he made to stand up just made him collapse. Once again, the Kamen Rider pulled out another bottle, but unlike the others, this one had a more simple shape, looking more identical to a regular water bottle. He twisted the cap open, and pointed it at the fallen Bakugo. He began to glow yellow, particles of light flowing into the bottle. When the light fully disappeared, Bakugo had turned to normal, and the Kamen Rider closed the cap, though the bottle was now bulbous, and now had a red tint to it. Bakugo breathed heavily, grasping his chest as if he had just ran a marathon.

“Ugh, what happened?” he muttered, as he started to get back up.

“There we go,” the Kamen Rider said, storing the bottle away. “No need to thank me, just doing my duty.”  
  
“As what!?” Death Arms said, as he and the other pro heroes surrounded him. “A vigilante beating up a civilian!? The hell are you supposed to be!?”  
  
“The Kamen Rider,” he replied curtly, with a shrug. “Though it's actually Build. Hm... Kamen Rider Build, I like the sound of that, don't know why I didn't put them together before...”  
  
“Well, whatever you are, you're going the station! Unauthorized hero work is a huge offense, buddy!” Death Arms said, cracking his knuckles, all of the pro heroes closing in on him slowly. “So just come with us peacefully, and answer a few questions.”  
  
“Ooooh, as much as I like the sound of that, I got to get going,” Build said, his hands on his hips and shaking his head. The white spring on his leg glowed red, and he leaped out from the circle, before anyone could grab him, and landed on a nearby rooftop. Bakugo regained his composure, and screamed at him, “Hey! Come back here, you bastard!”

He positioned his hands downwards, ready to send himself flying after him. But he couldn't. He tried again, but no explosions came from his hand. “What the-!? What the hell happened!? Why can't I use my Quirk!?”

“By the way, you're gonna be experiencing some temporary Quirk loss after turning back to normal,” Build said, offhandedly. “Don't worry, the longest it'll last is like, two, three days tops. Later!”

Before anyone could say any more, the Kamen Rider continued to hop from roof to roof, too fast for anyone to catch.

“Don't worry, I'll go after him!” All Might said, as he jumped to follow him. Everyone was left dumbfounded, though Bakugo was much more infuriated than anything. Izuku, on the other hand, was left with so many more questions.

That was unlike any sort of Quirk he'd ever seen before. In fact, it was so unlike any Quirk he's ever seen, that it had to be like, some sort of super science that he's never seen before. The Kamen Rider- er, Build- did so many fantastical things in that short fight. Changing forms, using different powers, turning Bakugo back to normal, it was incredible. But something about the bottles seemed... familiar. He didn't know why, or how, but he felt like he had seen them before.

Could Build have a connection to his kidnappers? Certainly, the gas bullet that hit Bakugo reminded him of the gas that he was doused with in his dream. Build's appearance didn't have any similarity to the lead kidnappers, though his mismatched eyes did sort of resemble their visors... There were so many questions, and it seemed like the only one who could answer them was the Kamen Rider himself.

* * *

It was some time after the fight, and Izuku had been walking down the neighborhood. The news reporters had surrounded Bakugo and the remaining pro heroes, hounding them each with question after question about what happened. Izuku was lucky enough to slink away undetected, since he wasn't the victim of two successive villain attacks like Bakugo was.

“Just what is going on...” he thought to himself, as he racked his brain over everything that happened today. “First I find out All Might's secret, made him drop that criminal, let that criminal capture Bakugo, and then someone shot him with a gas bullet that turned him into a rampaging monster. I just wanted to find-”  
  
“Young Midoriya!” All Might said, popping out from one of the side alleys between the houses. Izuku yelped in surprise, as he stared at his hero once again.

“A-A-All Might!? But why are you here!? I thought you were chasing the Kamen Rider!” Izuku stammered, falling backwards.  
  
“Indeed I was, but unfortunately, he really was fast!” All Might said, laughing a bit, before coughing up blood and turning back to his skinnier self. “But that's not what I'm here to talk about. I'm here to talk about you.”  
  
“Oh... well, I'm sorry again for what I did,” Izuku said, as he cast his eyes away from All Might. “I really messed up, I know, but-”  
  
“My boy, we all make mistakes,” All Might said, interrupting him. “Just like today, I made the mistake of telling you that you can't be a hero. And for that, I'm sorry.”  
  
“W-what do you mean?” Izuku said, looking up.  
  
“I mean that you have what it takes. I saw what you did there. You sprung to action to save your friend when no one else could. Of all the people there, the one person who was Quirkless and timid was the only one who acted! And you spurred me into action once again!”

“Many of the top heroes showed signs of greatness even as children, many of them claimed that their bodies just moved before they could think! Young man, I believe that, out of everyone I've seen, that you, are truly hero material!”

Izuku's chest felt heavy. He couldn't believe it. All Might apologized for telling him the truth. But this time, he was telling him that he had what it takes. To be a hero. That was everything that he wanted. Still, he couldn't let himself enjoy this relief. Not after what had happened.

“B-but how!? I have no Quirk, those other pro heroes, they were telling the truth!” he cried, tears streaming down his face. “How can I truly help others, when I don't have the power to do it!? I was kidnapped so recently, too! I'm too powerless to do anything!”  
  
“Which is why I deem you worthy of inheriting mine.”  
  
“W-what!?”

Izuku stared at All Might, trying to process what he had just said.

“I said, I deem you worthy of inheriting my power. I want you to be my successor, Midoriya,” All Might said, smiling.

“I-inherit!? But how!? Quirks are hereditary! There's no way-”  
  
“Oh, but there is. You see, my Quirk is unlike any other in the world. It is one that can be passed down, master to student! Each one polishes this Quirk, refining it until they pass it on to the next! I am the eighth holder, and I've chosen you, Midoriya, to be the ninth.”

“But I- well, it's true that the nature of your Quirk has always been a mystery, and there are a lot of theories as what it could be, since you've always kept it a secret, but to think it's something as big as this, that it can be passed on, it's incredible, I don't-”  
  
“Whoa, ease up on the muttering there, my boy,” All Might said, as Izuku snapped back to reality. “Yes, it's true, I've always deflected or changed the subject whenever my Quirk comes up. I have to, since the nature of it has to be kept a secret, since the world needs to think that the Symbol of Peace is a natural-born hero.”  
  
“The Quirk I will pass on to you, is known, as One for All.”  
  
“One for All...” Izuku muttered, letting the name of All Might's mysterious Quirk roll off his tongue.

“Now don't go thinking that I'll give this power over so easily,” All Might clarified, looking at him. “As you are right now, the power would be way too much. The next ten months or so will be very busy and tough for you. We'll need to train you so you can handle it. Otherwise, you might just explode.”

“Explode!?” Izuku said, before forcing himself to calm down. He thought it over. This is his chance. He's always wanted to be a hero, and a chance like this, a chance like this doesn't come by again. “... I'll do it. I'll become your successor.”

“Fantastic, Midoriya my boy! You'll be a great hero, no doubt,” All Might said, putting a reassuring hand on Izuku's shoulder. Izuku smiled, though a bit more sadly this time.

“Do you think we'll have time to figure out what happened to me when I was kidnapped while we train? Or what happened to Bakugo?” he asked, hoping that this big question of his will be answered too. All Might put a hand to his chin thoughtfully, pondering on what he could say.  
  
“Well, of course. Solving your mystery is just as important, my boy,” All Might said, finally reaching a conclusion. “Plus, you did theorize that whatever those people did to you, that it might've given you enhanced strength and speed, so you might plow through the workout I'm planning with more ease than without anything at all. I also want to answer a few questions myself, so this can work out.”

“I have to go now, my boy. Meet me tomorrow morning at Dagobah Beach, that is when we'll start training. You're on your way to become a fantastic hero, Midoriya, take pride in that.”

Izuku wiped the tears on his face with his sleeve. He couldn't believe his luck. From a mediocre morning, to an awful afternoon, all leading up to a fantastical evening. And All Might said it himself, he'll not only help him become a great hero, but he'll help him figure out the mystery of his kidnapping. Things were definitely looking up for him.

* * *

“Can you tell me why you did that, Bolt?” an armored man said, looking at his cohort. This man was dressed in black, with pipes protruding from his silver armor. A yellow bat insignia rested on his chest, his visor matching it. “We were doing so well in secret, too.”  
  
“Hmph, it was to test the long range Nebula Gas injection capabilities of the Transteam Gun's rifle mode, of course,” his ally replied, crossing his arms. He was dressed in gray, with black armor with pipes that formed a backpack-like device on his back, and a blue spanner that formed his chest insignia and visor. “As you can tell, Rogue, it's working perfectly. Now we don't need to depend on using the Nebula Chamber to test Nebula Gas compatibility.”  
  
“The Nebula Chamber is the most reliable way of testing compatibility and raising Hazard Levels, we won't just use the Transteam Gun recklessly, especially when the first target you used it on turned into a Smash. You can use that particular function however you like, but we'll still use the Nebula Chamber as the primary source of testing.”  
  
“You're being foolishly, Rogue,” Bolt said, dismissively. “We can't keep relying on just the Nebula Chamber. We have to use other ways of injecting Nebula Gas into people. Especially since it looks like you're gonna have to upgrade it to a larger size soon.”

Bolt walked off, his arms crossed. Rogue growled, and returned his attention to the Nebula Chamber, as his scientists tried to shove in a tall boy with six arms into the box, clearly struggling to fit him in. He punched two of them away, but they eventually got him inside, though it was definitely very cramped for him, unlike previous test subjects.  
  
“Tch... He was right about the chamber,” Rogue said, as the Nebula Gas flowed into the chamber, watching the boy writhing around, before he began his transformation into a surprisingly more manageable-sized Smash. "Should've gotten a bigger box for mutant-types."

**Notes for the Chapter:**

> \- I'm going with a broad strokes sort of writing with this story. Because of Build's nature as a series that only lasts a year and My Hero Academia's nature as a series that's still ongoing, Build's events are gonna be stretched out a bit to fit MHA. That's not to say that there's gonna be a divergence in where this goes, though. Like Sento having a job before the series rather than getting it in the first episode.  
> \- One of the things that I wish was a bit more of a focus is the Fullbottle collecting in Build. Since we don't really get that, I'm gonna go ahead and do it for this fic in particular. In this story, he collects more of them, though not all of them, since a few were already made. In addition, we're gonna see more Trial Forms and Best Matches before they become irrelevant. For the most part, I'll be making up some new abilities based on the Fullbottles, considering we never really get to see the full extent of them (thanks you Toei for cheaping out on special effects).  
> \- The biggest reason why I thought Build would be a good season to crossover with is that I think that the powers work in that season might provide an interesting interaction with the Quirks in MHA.  
> \- I'm gonna preemptively state that I'm not gonna use any of Build's crossover movies. That means no previous Riders appearing, sorry. I am open to giving Kaisei Mogami an appearance, but if I do, his story's gonna have to be overhauled and the like.  
> \- If this seems rushed and all, it essentially is. I want to get the first couple arcs of MHA out of the way so I can focus on original chapters and working on integrating the worlds better. Plus, there's just not that many ways to really, you know, change them, and a majority of the crossover fanfictions I've seen basically play it out similarly to the canon.  
> \- I'll probably come up with more unique titles for chapters later or on the suggestion of others, as long as the chapter titles deal with the chapter's contents, of course.  
> \- Despite the relationship tags, I'm not necessarily gonna go all in on writing like, pairings or whatnot. That's not really my thing, doing shipping and junk. If I feel like doing a pairing, I'll do it. Otherwise, don't expect too much romance here. I'm definitely having Ryuga and Kasumi as a pairing, though, since that's important.


	2. Chapter 2

**Summary for the Chapter:**

> Izuku starts building up his body, Build is hurt by mean words, and Bakugo's got the worst day ever.

**Notes for the Chapter:**

> So here's the game plan, I'm planning on updating this no later than two weeks at a time. I've been needing to do a fun project with a deadline 'cuz I've been creatively drained for too long, and because I've been kinda stuck on doing a couple of long term projects, and I think, "If I can manage to consistently do a fanfic, than I can apply that to my original writing, too".

Izuku grunted as he pulled on the rope tied to the trashed refrigerator. Just like what All Might had said a couple days ago, training to become the next vessel for One for All was tough. He had to clean up all of Dagobah Beach, since it had been covered in trash that drifted in from the ocean's currents, which people took advantage of to illegally dump their own garbage since no one could tell the difference. So far, it has been torturous, even with the enhanced strength he had gotten.

“I don't want to imagine how this would've been like if I didn't get stronger recently,” he muttered to himself, as he finally moved the refrigerator into the truck that All Might had gotten to carry the garbage to the proper trash facilities.

All Might was simply amazing for coming up with such a training regiment within a short period of time. The schedule he had given him factored in his school work, and took advantage of every space of time he had available to train his body. Not to mention that it allowed him time to work on solving the mystery of his kidnapping.

“How you're holding up, Midoriya?” All Might asked, as he sat on top of one of a broken washing machine. “I see that you've gotten quite the trash heap on that truck! That's pretty good, I didn't think you'd be that fast with gathering all that garbage.”  
  
“I'm doing fine, All Might,” Izuku replied, wiping the sweat off his brow. “I think I'm gonna have to call it a day soon, though, since I have to get to class soon.”  
  
“All right, but remember to head back here as soon as you can! We have to use as much time as we can to help refine your body!”  
  
Izuku nodded, saying goodbye quick, before heading home to wash up and get changed. Couldn't smell like sweat and sand at school, after all.

* * *

The day before yesterday was a really busy day for him. Getting smacked by that sludge guy, working a full time job at the Institute, saving that explosive kid who got held hostage by the same sludge guy and got turned into a Smash? And then going back to work like nothing happened the day after? He was worn out.

At least until he heard a ding. A tuft of hair sprung up in a cowlick, as a giant grin spread across his face immediately, and he rushed over to the machine. It was a large, metal cube with a sliding door, and next to the door was a microwave sort of contraption. He opened the microwave, and pulled out the bottle that was inside. It was red, with a bird-like creature taking its shape.

“Oh, so we got the Phoenix Fullbottle?” he said, marveling at the bottle. “Makes sense, considering that explosive kid, huh, Misora?”

The door to the machine opened, and a short girl with short black hair with a ponytail sprouting from the top of her head walked out. She squinted at the man for a bit, before muttering, “Tired... Sleepy... Want my money, Sento...”

She walked off slowly, before plopping herself onto a nearby couch to sleep. The man, Sento, sighed and shook his head. “I'll give it to you when I get my next paycheck tomorrow,” he said, as he headed towards a work bench with his belt on it. “Let's see... how about Gatling and Phoenix?” he muttered, inserting the Phoenix Fullbottle and a gray one that was shaped like a gatling gun barrel into the belt.

“ **Phoenix! Gatling!** ”  
  
“Hm, didn't work... how about Phoenix and Jet?” he said, taking out the Gatling Fullbottle and replacing it with a blue one shaped like an airplane.

“ **Phoenix! Jet!** ”  
  
“No, not it either...”

“Hey Sento!” a voice called out from the top of the stairs. Sento turned around from his work bench, and saw Misora's father, Souichi Isurugi, coming down. “Turn on the news, they're talking about Build.”  
  
“Really!?” Sento said, as he grabbed the remote and turned on the TV. Sure enough, there he was, a clip of his fight against the explosive kid's Smash form (“Hm... I guess he could be called the “Explode Smash, all things considered,” he thought). At the bottom of the screen was the headline, “Who is Kamen Rider Build?”

“Oooooh, that's some good footage they got!” Sento said, a manic grin spreading on his face. At least until the newscaster opened his mouth, questioning Kamen Rider Build's integrity, and if he was the one responsible for turning the explosive kid into a monster. For the next few minutes, the airtime was full of interviews from pro heroes who also questioned his objectives and bystanders who were just amazed that the Kamen Rider even existed.

“How rude! Kamen Rider Build would never turn people into Smashes like that!” he said, aghast at the accusations that were being thrown at him, though the bravado did give way to uncertainty. “Wish I knew where the people who do are, though.”  
  
“Hey, don't sweat it, Sento!” Souichi said, giving him a hard pat on the back. “You're doing a great job so far, so be proud of that!”

Sento grinned. It had been a few months since Souichi found and took him in, helping him with housing and giving him the resources he needed to become Build. Sure, there have been some rough bumps (mostly the first time he fought as Build, since he didn't know what he was doing, and that Fang Smash really did a number on him, though at least he got that Lion Fullbottle), but he got the hang of it after a while. He checked the clock, and jumped up from his chair.

“Oh man, I'm gonna be late! I gotta go, Owner, see you later!” he said, grabbing his coat and belt. He climbed up the stairs, and out through the secret mini-fridge entrance. Once outside, he inserted the Lion Fullbottle into his cellphone, and watched it transform into a motorcycle.  
  
“Welp, today's a new day, hope nothing goes wrong for me.”

* * *

Everything had been going wrong for Bakugo for the last two days.

He got attacked not by one, but two villains, and some asshole vigilante who's gear was way too advanced and strange for his taste. And not only that, but his Quirk was now gone. Sure, that vigilante spouted something about it being temporary and only lasting two to three days, but just one day was just one too many for him. Not to mention that he was forced to skip class by his parents who coddled him over the whole situation, which ruined his perfect attendance record.

As he walked into his classroom, his worthless classmates stopped whatever they had been doing to just stare at him. He scowled, and made it over to his desk, trying to ignore the weird looks they were all giving him.

“Hey, Bakugo, think fast!” one of them finally said, tossing a small rubber ball right into his face. Bakugo tried to blast it away with one of his explosions, but nothing happened, and it collided smack dab on his cheek, knocking him out of his chair.

“Holy crap, it's true, he's lost his Quirk.”  
  
“Wow, couldn't have happened to a better guy.”  
  
“Looks like the king of the school's been dethroned.”  
  
Fuck, they were all looking down on him now. He growled, and slammed his hands onto his desk. “Shut the fuck up! It's only temporary, so don't get used to it!”

His classmates chuckled, as if they weren't intimidated by him anymore.

“Boy, that's tough talk from someone who's as useless as Midoriya right now.”

“Pft, Bakugo's pretty much nothing without his Quirk.”

“Always hated his guts anyways.”

“Hey Kacchan.”  
  
Bakugo scowled and turned to face Deku. That miserable bastard stared at him with pity. It was unbearable. To think he'd be reduced to his level.

“Go the fuck away, Deku, I don't need your pity,” Bakugo muttered, looking away. “Unlike you, my Quirklessness isn't permanent, so back off.”  
  
“Bakugo I-”  
  
“Alright, everyone settle down,” their teacher said, finally entering the room. “Now, I know that a few of you,” he said, glancing over to Bakugo and Deku, “had a pretty crazy couple days, but for now, I just want you all to focus on class, is that clear?”

The class muttered a weak “Yes, sir,” and it wasn't before long that the lesson started for the day. In between classes Bakugo had to deal with the jeers and taunts of his worthless classmates as he struggled to force an explosion to come out of his palms. It wasn't until school was over and he was outside that his troubles really started that day.

“Hey, Bakugo,” a cold, hard, deep voice said. Bakugo turned around to face Ishishishi, a guy two years his junior whose mutant-type Quirk made him a giant rock man with rocky mane-like hair. “Heard your Quirk's gone.”  
  
“Yea, and? It'll be back soon, so what about it-”

Ishishishi picked Bakugo up by the scruff of his shirt, and grinned. “That means that you're no longer the big man on campus, and that I can take your place.”  
  
“Oh come off it, Ishishishi, we all know that when the sun's gone, you freeze up and turn into a statue,” Bakugo growled, not intimidated by Ishishishi in the slightest. “So let go, and I promise you that I won't break-your stony ass into a thousand pebbles when my Quirk comes back-”

Ishishishi slammed Bakugo against the wall that surrounded their school, not amused by Bakugo's defiance. “I guess before you do that, I'm gonna have to send you to the hospital. You don't get it, but without your Quirk, you're nothing.”

“Leave him alone!”

Bakugo and Ishishishi turned their heads, and saw Deku looking at them. Bakugo's scowl grew larger, as he muttered, “I told you, I didn't need your help before, and I don't need it now! Now buzz off, and let me handle my own business!”  
  
“Seriously? You?” Ishishishi laughed, shaking his head. “At least Bakugo's Quirklessness isn't forever. You? Just stay out it, and hope that I don't snap you in two.”  
  
Ishishishi refocused his attention back onto Bakugo, who just gave him the most defiant scowl he could muster, while he readied his rocky fist for a punch. When he got his Quirk back, Ishishishi's gonna pay dearly.  
  
Their staredown got interrupted once again, but this time, Deku barreled into Ishishishi, knocking the stone giant boy to the ground. Before anyone could really process what was going on, Deku grabbed Bakugo's wrist, and ran off with him in tow, everyone too stupefied to understand what just happened.

* * *

“You bastard!” Bakugo scowled, once Ishishishi was out of view. He wrenched his hand out of Izuku's grasp, and glared at him. “I had that under control, So I didn't need your worthless help!”

Izuku froze. He never meant to slight Bakugo's pride like that, but he just couldn't let what was happening slide by. It wasn't fair. No one deserved to be Quirkless, permanent or temporary. In the moment, he related a lot to Bakugo's plight, since it's been like that all his life.

“I know, it's just... I can relate with what you're going through,” Izuku said, looking away.

“Shut up.”  
  
“Kacchan, I know you can bounce back from this, but it doesn't hurt to have someone support you in the meantime. I know for one thing that I would've liked a friend to help, and-”  
  
“I said shut up!”  
  
Bakugo shoved Izuku away, scowling. “I don't need anyone's pity! I don't need yours, my parents', anyone's! So I'm Quirkless for a few days, big fucking whoop! I'll plow through this, no sweat! This is nothing but a small road bump, and I'm not gonna let this stop me!”

Izuku looked at him. It was true, this was just a temporary setback for Bakugo. That was what he admired about him, that endless drive to become the best, even if the odds were against him like this. He took a deep breath, and smiled.  
  
“Alright then, I'll let you be, but I want you to know this, Kacchan,” Izuku said, as he steadied himself. “I'm still aiming to be a hero, and like you, I'm not gonna let anything stop me anymore! Just you watch!”  
  
Bakugo stared at him, and scoffed. “Fine, whatever. You can keep dreaming like the idiot you are. Your stupid burst in strength isn't gonna carry you as a hero.”  
  
He turned around, and walked off. Izuku sighed, and started to head off in the opposite direction. He had to get back to his training, after all. Nothing was gonna stop him from becoming a hero.

* * *

By the time Izuku had returned to Dagobah Beach, he heard some noise coming from the garbage heaps. He headed towards what was causing the noise, being sure to be as stealthy as he could to avoid detection. When he peered around the corner, he gasped. He saw another creature, one that looked similar to how Bakugo had when he had been transformed by the gas bullet. This one looked more akin to a giant mechanical hand with two legs crushing a rock, with its arms looking like the pinkie and thumb, while the remaining three wrapped around its “rock” torso. The middle finger had three holes on the fingernail, making it seems like that was where its face was.

“The guy who transformed Bakugo must've done this,” he thought, as he peered at the creature, who wandered aimlessly around the trashed beach, sometimes smashing a refrigerator or two with its giant finger-like arms. “Doesn't seem like anyone is nearby, so they must've dumped this guy here... All Might's coming soon, I should tell him-”  
  
As Izuku moved to make his way to his meeting place with All Might, a piece of unbalanced debris fell from atop of the trash pile he was hiding behind. He instinctively jumped with a yelp, managing to dodge the debris. Unfortunately, this alerted the creature, who started to walk over to investigate.

The creature caught sight of him, and when Izuku started to run, the creature followed. Fortunately, it wasn't too fast to catch up, and Izuku used the labyrinth of garbage to lose it. Unfortunately, it didn't seem like it was running out of stamina anytime soon, and it was also plowing through the garbage piles, leaving holes where it had ran through.

Izuku stole glances back to check how far back that creature was, trying to figure out how to lose him more effectively, when he tripped over a piece of discarded wood, falling over. As he turned over to stare at his imminent demise, a familiar red-and-blue blur rushed in and punched the creature right in its face(?).

“Phew, almost didn't make it there,” Build said, shaking his hand. “Good thing I was nearby when I got that Smash alert. Don't worry, kid, I'll take care of this.”

Build dusted off his hands, and resumed his assault on the creature. “He said 'Smash alert', so I guess they're called Smashes,” Izuku thought, wondering if the name was some sort of mockery of All Might's attack names.

The Smash swung its arms wildly at Build, who dodged and block each attack. Build summoned his drill-sword-gun weapon thing from his belt, and started swinging the spinning weapon against the Smash, though it was largely unaffected by the attack.

“Oooh, you're a tough guy. Guess that'd make you the Tough Smash, then? Hm... nah, how about Strong Smash?” Build quipped, as his weapon disappeared. The Strong Smash growled, and managed to swing one of its fists into Build's gut, knocking him back a bit. “Oof, nice punch you got there! Gotta keep my distance. Guess I'll try using a little more firepower. And I did want to see how this Trial Match worked, anyways.”  
  
Build pulled out the bottles in his belt, and pulled out two new ones, a red one shaped like a fiery bird, and a gray one shaped like a gatling gun barrel. He shook the bottles and untwisted the caps before inserting them into his belt and cranking it.

“ **Phoenix! Gatling! Are you ready?** ”  
  
“Build up!” Build exclaimed, as his armor changed. The red parts of his armor stayed red, though this time a slightly different shade. His right shoulder pad was now shaped like a flame, with a matching flame-like blade on his right forearm, and his left eye was now shaped like a fiery red phoenix. The blue parts, on the other hand, were now a gunmetal gray, his left shoulder armor resembling the stock of a gun, and his right eye was gray in the shape of a gray gatling gun. On the upper left side of his chest was a red flame, and a series of “bullets” came across his chest like a bandolier. On his back was a segmented cape that looked like flaming feathers.

The Smash charged towards Build, who jumped into the air and flew over it. A gatling gun barrel formed underneath the flame decoration on his chest on the gunmetal gray parts of his armor, and fired a salvo of fireballs at the Smash, who was too slow to dodge any of them, and was knocked back by the explosions.  
  
“Hm, combining Gatling's ability to create gatling barrels on its side with Phoenix's firepower is a good idea, but considering that creating them takes a lot out of me, I should really work on creating a weapon for Gatling instead,” Build said as he landed. “Back to RabbitTank to finish this, I suppose,” he added, as he changed forms once again, though Izuku could've sworn he heard Build mutter something like “Figures I'm forced to use the only Best Match I have.”

The Smash started to charge towards Build, who began to crank his belt once again, setting up the same attack from yesterday. Once Build finished cranking his belt, he ran away, only to create another hole that he jumped in, where a pillar immediately shot out of, while a sloping graph formed that pinned the Smash in place.  
  
“ **Ready, go! Vortex Finish!** ”  
  
And just like before, Build slid down the slope, and landed a powerful explosive kick that sent the Smash flying back, weakened from the attack. Once he landed, he pulled a blank bottle out, and twisted it cap, sucking in light particles from the Smash. Where there was a Smash, was now a tall, muscular white-haired boy with six arms and a mask. But the clothes he was wearing, the torn-up white cotton shirt and pants, made Izuku freeze. Those were the same type of clothes he was find in after his kidnapping.

“And that's that,” Build said, closing the cap of the now-bulbous brown bottle. He looked at the former Smash, who groggily looked around before falling over unconscious. “Hm, I guess people with mutant-type Quirks don't experience temporary Quirk loss like emitter or transformation types do. At least, surface level wise. Should move this guy outta here, I personally wouldn't want to wake up in a trash heap like this.”

“H-hey,” Izuku said, as he watched Build pull the youth towards the street, grunting as it seemed like the boy was much heavier than he anticipated. “Build! Can you tell me what's going on with all of this!?”  
  
“Sorry kid, I don't really have the time to explain this, especially since you probably wouldn't comprehend it. Gotta need a big brain like mine to do that,” Build said, a bit dismissively. “Plus, can't let any of those pro heroes, police officers, or Guardians see me. Seriously, those were some real hurtful words they were all calling me on the news.”  
  
“B-b-but-”  
  
“Just gonna ask that you tell this guy what happened and all, since I'm sure he'll have questions when he wakes up. Hope you have a good day, doing whatever you were planning to do at a messed up beach,” Build said, as he prepared to jump away.  
  
“Can you tell me anything about the bat, cobra, and spanner men!?” Izuku blurted out, freezing Build in his place. “I... I feel like whatever has been happening, those guys are at the center of it all. And well, you kinda look like them, since your eyes are shaped like objects, and their visors are, too, and-”  
  
“You've seen the bat man?” Build said, hesitantly. “And there's a cobra man and a spanner man, too?”

“Y-yes!” Izuku said, nodding his head. “Well, it's more like a dream I had of them. You see, I was kidnapped some time ago, and I was found dumped in a completely different place with some amnesia. Ever since then, I've been having the same dream of being trapped in a box, being experimented on, and those men... So do you know who they are!? D-did they turn me into a Smash!? So did you save me, too!?”  
  
Build stood there, thinking deeply.

“No. I didn't. I remember all of the people who I saved, and I'm sorry, but you weren't a Smash. But maybe... maybe you're just like me. They experimented on me, too, and they took all my memories somehow,” Build said, walking over to Izuku. He grabbed him by the shoulders, excitedly. “This is perfect! I finally have a real lead! Most of the people I save either don't remember what happened quickly enough to tell me or stay unconscious for too long that I can't hang around! Can you tell me anything else? What did their lab look like? Did you check the area where you were found in? Can you lead me there!?”  
  
“Well, I-” Izuku began, when he heard All Might calling for him.  
  
“My boy, I heard a commotion, and I came as fast as I could-” All Might said, jogging towards them in his skinny form. He paused when he saw the Kamen Rider. “You!”

“Oh, that's not good. I can't stay around here to let him call a pro hero or something,” Build said, looking at the skinny man. “Listen, we gotta go, kid.”  
  
“Wait, what do you mean-”  
  
Build picked Izuku up in a bridal carry, and jumped into the air, leaving All Might behind. Izuku screamed, as Build hopped from rooftop to rooftop. “W-wait, calm down! There has to be a better way to handle this!”

“Relax, when we're done, I'll take you back to your dad, no sweat,” Build said, causing Izuku to sweat at the thought of having _All Might_ as a father (which would be pretty amazing, to be honest).

“H-he's not my dad! I mean, I wish he was,” Izuku said, as Build jumped from another rooftop. “I mean, not that I don't love my dad, he's just working overseas a lot.”  
  
“Well, whoever that guy is, there's no way he's catching up to me, so we can-”  
  
“HAVE NO FEAR, _FOR I AM HERE!_ ”  
  
Build turned to look back, and saw a rather furious All Might following him, practically seeing the steam coming out of his ears and mouth. “Holy smokes, it's All Might! How did he find me so fast!?”  
  
Frantically, Build booked it out of there as fast as he could, knowing that yesterday's escapade from All Might was sheer luck, and that he had a head start and hid in an alleyway far too small for someone as big as All Might to go down into easily. But something seemed off about All Might today. For one thing, he was wearing the same set of clothes that other guy was wearing, and there was no way that guy could've called for a pro hero that quickly. So the only other reason for him to have found him-  
  
“Wait... that makes too much sense,” Build muttered, as he kept taking glances back at All Might. “No wonder I didn't see him back then, he was in that other form!”  
  
“Uuuuuh what other form?” Izuku said, trying to play stupid, though he quickly realized that it would've been smarter to just not say anything.  
  
“Well, that just confirms my suspicions,” Build said, as he came to a stop, as All Might slammed onto the rooftop.  
  
“You have 10 seconds to let young Midoriya before I-”  
  
“Okay, okay, there's a huge misunderstanding. I didn't mean to kidnap him. So let's just talk, All Might,” Build said, as he let down Izuku gently.

“And why should I listen to you?”  
  
“Well, for one thing, the only person that saw me take him was that skinny guy at the beach, who was wearing the same clothes as you,” Build said, crossing his arms. All Might froze in place, though his furious glare didn't die down. “I'm taking a wager that that's your real form, and that the one you're in right now, is simply just your Quirk expanding your muscles and power.”

“And what about it?” All Might said, clutching his face. “That doesn't change the fact that I can still fight you.”  
  
“I know, but let's trade secrets,” Build said, pulling out his bottles and taking his belt off. His armor dissipated, leaving behind a man with short black hair, a shirt that's split down in the middle, one half red, the other half blue, jeans, one blue shoe and one red shoe, and an oversized brown overcoat. “My name's Sento Kiryu, and I'm Kamen Rider Build. You don't need to hold that form for this conversation, because from my observations, you're actually running low on energy, and that steam's coming off of you is an indicator that you're reaching your limit.”  
  
“How did-”  
  
“From my observations of videos and news articles about you, you've been slowing down on your hero work to about three hours a day, which how I reached that conclusion, and a couple of phone videos from random bystanders have shown a faint steam coming off of you at times. And since that's the case, I assume that this kid-” Sento said, pointing to Izuku, and a tuft of hair started to rise up, “-must be your apprentice or something, since you clearly knew who he was, and he seemed to know about your skinny form. Am I right so far?”  
  
“... How did you think all of that up?” All Might said, apprehensively, though the hesitation did give Sento the answer he needed.

“Well, my Quirk's not called 'Big Brain' for nothing, you know,” Sento said, his smile slightly smug as he pointed to his head.

* * *

_**Sento Kiryu! Quirk, Big Brain! It enhances his intelligence to genius levels, grants him acute observational skills, and gives him an impeccable memory! Any book about science or language he reads, he instantly understands and comprehends it all! Unfortunately it doesn't work quite as well with other fields such as the fine arts or history, or anything that he doesn't have an actual interest in really, and any theories he makes he still has to test to confirm!** _

* * *

“But in any case, you can trust me, All Might. I don't have any intentions of telling anyone your secret,” Sento said, crossing his arms. “Besides, I already let you in on my own big secret, so it's all balanced, right?”  
  
All Might stared at him, and sighed. At that point, he released his transformation, and returned back to his skinnier form. “Alright, you win. What do you want from young Midoriya, Mr. Kiryu?”  
  
“I want to help him find out about the men who experimented on him,” Sento said, as he sat down on the floor. “I've been trying to find those guys for months, since they did the same thing to me, and all those other Smash subjects.”  
  
“'Smash'? Is that what they're called?” All Might said, raising an eyebrow.

“Yea. Didn't come up with the name myself, not sure why they're called that, beyond the fact that they have a preference to break as many things as possible,” Sento said, scratching his head. “Anyways, back on subject. I only took him to see if I had a lead on where those guys are. You said you don't remember where they took you, right? But you do remember where they left you”  
  
“Y-yea,” Izuku said. “I can lead you to where I was dumped. We might be able to find some clues or something there.”  
  
“That sounds like as good a plan as any, I suppose, considering our limited knowledge,” Sento said, getting up. “I'll take you there, and we'll scour the area as much as possible to find anything.”  
  
“Count me in, too,” All Might said, pointing to himself. “If anything goes wrong, you could use the backup, even if you're the Kamen Rider. Besides, Midoriya's my responsibility as, er, my apprentice. If I can't help him out with his biggest mystery, than what kind of mentor would I be?”  
  
“Alright, but we'll probably have to take a car there. I only have a motorcycle, and I don't think having All Might be seen with the Kamen Rider would be good for your image. At least not until they stop saying all that stuff about me.”

* * *

Fortunately for them, All Might still had the truck that he and Izuku were using to take the garbage they were collecting to the proper dumping sites, while Sento used his motorcycle (the two of them still couldn't believe that his smartphone could turn into one with one of those odd bottles he used) to follow them. With Sento being out of earshot, All Might said to Izuku, "While Mr. Kiryu seems to be trustworthy for now, we mustn't let him know about the true nature of One for All. At least as long as possible. Who knows how long it'll take for him to figure out with that Quirk of his?"  
  
"I understand, All Might," Izuku said, nodding in agreement. "Still, it's hard to believe that someone like him exists. The only other person I know about with super intelligence like that is U.A.'s principal, Nezu."  
  
"Well, I wouldn't say that. There was Takumi Katsuragi."  
  
"You mean that former Institute scientist that was murdered a couple months ago by the ex-boxer and sidekick Ryuga Banjo?"

"Yea, that's the one. He was a smart guy, all things considering. Sure, there were a couple of malicious rumors here and there I heard about him, but he seemed to be an alright guy when I met him. Still, if there was anyone who could've figured out about One for All on their own, it probably would've been him."

"So it's of utmost importance that we can't slip up, because who knows what'd he do with that information?" All Might ended, as Izuku vigorously nodded. While Sento did seem to be an alright, if somewhat smug, man, they really didn't know him that well yet to trust him with any more secrets. So for the moment, they'll just have to deal with him knowing about All Might's true form. 

After nearly an hour and a half of driving, the three of them made it to the abandoned warehouse that Izuku had been found at. Once they got out off their vehicles, each one of them began to scour the area for any clues they could find. In between examining each empty crate and barrel, All Might and Izuku would ask Sento questions about his powers and weapons, since they were nothing like anything they've ever saw.

"So what are the little colored bottles you use with your tech?" Izuku asked, looking through a utility closet.  
  
"Oh, those are Fullbottles. They're the purified essence of the Smashes that I collect," Sento said offhandedly as he shifted through wooden pallets. "Each of them provide different abilities based on what they are. So far I have Rabbit, Tank, Phoenix, Turtle, Gatling, Lion, Pirate, Beetle, Jet, Vacuum, and Refrigerator. And whatever this one's gonna be. By inserting them into my belt, the Build Driver, I can transform into Build."  
  
"And your forms?" All Might inquired, as he walked up to the second floor catwalk.   
  
"Oh, those are easy. There are the Trial Matches, which are the ones where I match random Fullbottles together. And there are Best Matches, where I match a Fullbottle with the correct corresponding partner to get the strongest abilities out of both. Not to say that Trial Matches aren't useful, though, since there can be certain situations where using a Trial Match is better than using the Best Match. At least, theoretically. I've only found RabbitTank." 

"How did you come across this tech? Did you make it yourself?" Izuku said, sighing as it became apparent that there really wasn't much they could find here.   
  
"Oh no, I wish. I mean, I got the hang of it, and I do build a lot of the newer tech, but it's all thanks to-" Sento began to say, when they were interrupted by a sudden growl. They fell silent, searching the area for the source of the growl, while he put his belt on.   
  
Suddenly, a Smash broke through one of the walls, knocking it down. Sento immediately inserted the Rabbit and Tank Fullbottles into the Build Driver, and cranked it as fast as he could. Tubes came out of his belt to form runners with his armor, the red Rabbit half in front, and the blue Tank half behind him.   
  
" **Rabbit! Tank! Best Match!** **Are you ready?** " the belt asked him. Sento answered with a firm reply. "Transform!" 

" **The Moonsault of Steel! RabbitTank! Yeahhh!** " the belt announced, as the runners slammed onto Sento, forming his Kamen Rider armor. 

The Smash that appeared before them seemed to be especially robotic in nature. Its armor-like flesh exposed wire-like skin, with two powerful clamps for hands, and a wide torso that had large headlight-like lightbulbs on its chest, and exposed gears whirred in its abdomen. Its shoulders had gun-like attachments, and its head was robotic-like, almost like a Guardian's head, but with three large telescoping eyes on it, and wire-like "hair" growing out just above its neck. It growled, and ran towards Build, firing bullets out of its shoulders. 

Build summoned his sword-drill-gun weapon, and tried to smack the bullets away, but a few of them moved around his weapon and struck him in the back.   
  
"Ouch! Homing bullets? That's not fair!" Build said, as the Smash got close and started to swing punches at him.   
  
"Don't worry, I'll help!" All Might said, as he began to bulk up.   
  
"No, don't! Only Build's able to safely extract the Smash essence! Fighting without a Build Driver won't work!" Build said, blocking an attack from the Smash. "Appreciate the offer, though!"  
  
All Might frowned, as he released his muscle form. He didn't like that. He didn't want to be helpless when others are in danger, especially knowing that whoever this person was didn't deserve to be turned into a monster like this. The future hero-in-training clutched his fists, too, trembling as he watched Build fight. 

Build pulled his weapon apart and reattached the blade to the handle to form its gun mode, and began firing at the Smash. It jumped away to avoid the spray of bullets, though it didn't dodge of them in time. Grunting, the Smash stuck out its right arm, and its hand fired out like a grappling hook, grabbing and pulling Build's gun away.  
  
"Huh, neat trick. Guess I should call you the Claw Smash, since you're like those claw games with hands like that," Build said, as the Claw Smash launched its left arm to grab him. He backed up just enough to be out of its range (though he did stumble a bit on an errant plank of wood that was behind him), and pulled out the Fullbottles out of the Build Driver. "Since this place is so messy, let's clean up with a little bite, shall we?"  
  
He inserted the Lion and Vacuum Fullbottles into the Build Driver. " **Lion! Vacuum! Best Match!** "  
  
"A Best Match? Finally, something new! Let's go!" Build said excitedly, cranking the handle as a new set of equations appeared around him and the Smash. Runners came out of his belt, with the front forming the marigold Lion half, and the back forming the turquoise Vacuum half. " **Are you ready?** " **  
**

"Build up!" he announced, as the runners slammed onto him, forming the Best Match's armor. " **The Mane Cyclone! LionCleaner! Yeah!** "

The right arm of LionCleaner was a shining marigold color, with a lion head-shaped gauntlet and a tail-like protrusion on his shoulder armor. The turquoise left arm, on the other hand, in place of a hand, had a vacuum cleaner-like attachment over it, with a tube attached to it that led directly into a case-like shoulder armor. Build's right eye resembled a vacuum cleaner, while his left eye resembled a lion's head. "I've found the winning formula," he said, as he traced the "nozzle" of his eye with the back of his right index finger before doing a hand flick. 

The Claw Smash roared, and it launched both its clamp hands towards Build. He stuck out his left hand, and fired a powerful blast of wind at them, sending them flying back into the Claw Smash's face, knocking it backwards. 

"Wow, the Long Range Cleaner's blowing power's more than doubled!" he stated giddily, as the Claw Smash prepared to fire its shoulder guns. Before the bullets could curve around him, Build sucked all of them up, and fired them back, knocking the Claw Smash down. "Same with its sucking power. Now, let's try out the Lion half!" 

Build clutched his right hand, and a bright yellow energy began to coat it. As the Claw Smash struggled to get back up, Build threw a punch, sending a small energy projection of a lion's head into it, knocking it back down.   
  
"So I can launch punches with the Gold Lio Gauntlet! That makes up for the charge time."  
  
Build used the Long Range Cleaner's sucking function to pick the Claw Smash up, and punched it with the Gold Lio Gauntlet. After repeating this a couple of times, the Claw Smash seemed to be sufficiently weakened. "Alright, time to finish this!" Build announced, cranking the Build Driver's handle. " **Ready, go!** "

Build stuck out the Long Range Cleaner, and it began to suck the Claw Smash towards him, though much faster than before. Once it got stuck in the nozzle, Build lifted it up, and shot it into the air. A large lion head projection formed around his right arm, and he sent it flying into the Claw Smash, exploding upon contact. " **Vortex Finish!** "

When the Claw Smash landed, Build pulled out an empty bottle, twisted its cap open, and pointed it at it, sucking up the glowing Smash essence. When he was finished, the Claw Smash turned into a young curvaceous girl, roughly around Izuku's age, with pink dreadlocks, and yellow eyes with crosshair-like pupils. Unlike the boy from earlier, she was dressed in a school uniform, though it was different from Izuku's. All Might entered his muscle form, deciding that if he couldn't help bring this girl to normal, he could at least comfort her.   
  
"Ugh... what happened?" she muttered, looking around. "Where... where am I?"  
  
"It's alright, you're safe now," All Might said, with a hearty laugh. "You were turned into a monster, but thanks to the Kamen Rider, he helped turn you back to normal!" 

"The Kamen Rider!?" the girl said, almost excitedly, but she immediately clutched her head and moaned. "Oh man, I'd be more happy if it weren't for this splitting headache." 

"Do you remember what happened?" Izuku asked, looking at her. "Did you get taken to some lab or anything?"  
  
"I was going home to mine, yea."  
  
"Yours?" 

"Yea, I wanted to work on the gear I wanted to submit for my admission test for U.A's support course, but then this weird gas trail came out of nowhere and hit me in the chest. Next thing I know, I'm here," the girl said, rubbing her head. "Eugh, can we go somewhere else? I need to nap for like, a few days..." 

Before anything more could be said, a squadron of robotic Guardians came into the empty warehouse, surrounding them. "Guardians?" Izuku said, puzzled. "I didn't think there was a troop nearby..."  
  
"Something's not right about them," All Might muttered, as he walked to the girl's side, picking her up in a bridal carry. Build clutched his right hand, letting energy charge in it. Even Izuku got into a fighting stance, though admittedly it was a bit awkward looking since he hadn't practiced yet. The apprehensive group stared at all of the Guardians when they heard a strange slow clapping.   
  
"Congrats on beating that Smash so quickly," a garbled voice said, as the Guardians parted to reveal the voice's owner. He was dressed in a gray leather-like undersuit with black armor, with black pipes resting on his back like a jetpack of sorts, and thin black spanner-shaped bars rested on his gauntlets. On his chest was a blue spanner, and his helmet's visor likewise matched it, while a smokestack-like horn rested above it. 

There was no doubt about it. This was the spanner man from Izuku's dreams. 

"Honestly I thought that one was pretty excellent, having the ability to generate its own ammunition that could home in on its targets and having grappling claws like that, but I should've figured that the Kamen Rider would've figured out how to beat it," the spanner man said, crossing his arms. "Still, that was some valuable data I gathered from that fight."  
  
"You-! You're the spanner man!" Izuku said, tensing up.

"Spanner man-? Hm, I suppose I haven't introduced myself yet. My name is Meta Bolt," the spanner man said. "As for why I'm here, I suppose I wanted to test the Kamen Rider myself for once. As intriguing as the Smash experiments have been, I figure gathering data firsthand would be more, enlightening."  
  
"You..." Build said, his hands tightening. "You've been turning people into Smash, just to experiment?"

"Well, that's not the only reason. However, I don't think I'm in a place to say why yet. My coworkers wouldn't appreciate me spilling everything too quickly," Meta Bolt said, as a strange gun materialized in one hand and a strange blade in the other. The blade was the oddest, having a valve on the side and a scope on top for some reason. He added with a chuckle, "Hey, maybe if you beat me, I'll tell you more." 

"People aren't just yours to experiment!" Izuku said, the joints in his fingers popping from his clutched hands. "You're turning people into monsters! What kind of scientist are you, ruining people's lives like that!?"  
  
"Tch, like a kid would understand," Meta Bolt said, popping his neck. He gestured to Izuku with his gun, and spoke to the Guardians. "Hey, take him. We can probably do more experiments on him. Was definitely a waste to just let him go like that."

Izuku tensed up, ready to use whatever little super strength he had gained to protect himself. But All Might was having none of it. "Mr. Rider! Can you handle fighting this villain and rogue Guardians by yourself? I'll take young Midoriya and the little miss here to safety!"  
  
"Be my guest!" Build said, rushing towards Meta Bolt as All Might lifted Izuku onto his back, and leaped out of a broken window. "Let's go one on one, Screwloose!" 

The Guardians started firing their guns at All Might, but Build used the Long Range Cleaner to suck up their bullets, and fired them right back at them, damaging them enough to shut down. He returned his attention to Meta Bolt, who had closed the gap between them, and swung down his blade onto Build who blocked it with the Long Range Cleaner's nozzle. 

"Well done taking out all those Guardians at once!" Meta Bolt grunted, as sparks flew between their weapons. While Build was distracted with this, Meta Bolt fired his gun right into Build's stomach, knocking him back with a small explosion, following up with more shots. "But I'm on an entirely different level than any Guardian or Smash!" 

Build grunted, and charged energy into his right fist, launching several small but quick energy punches. Meta Bolt stopped each one, either by firing into the energy punch before it could get close to him, or by knocking it aside with his blade. On the last one, Build charged longer, and fired a much stronger punch towards Meta Bolt. He simply thrust his blade into the punch, dispersing the energy in a large explosion, which kicked up a great amount of dust, obscuring both of their visions. Meta Bolt didn't have time to blow the dust away when he saw the cloud being sucked in by Build's Long Range Cleaner, and with it, his blade, which landed point first into the nozzle. 

"That takes care of that," Build muttered, only to notice Meta Bolt charging towards him, firing bullet after bullet at him. Build blocked each one, only for Meta Bolt to grab his blade's grip, though it was still stuck inside the Long Range Cleaner. 

"Smart of you to disarm me like that," he said, complimenting Build. "Too bad there's more to the Steam Blade and Transteam Gun than that!" 

To Build's surprise, the grip popped off the blade, only for Meta Bolt to insert his gun in between the blade and handle. The combined weapon announced " **Rifle Mode!** ", much like Build's own Build Driver, and Meta Bolt spun the blade's valve. " **Ice Steam!** "  
  
Meta Bolt fired his weapon into the Long Range Cleaner, as frost formed inside and out of it, clogging it. He kicked Build, pulling his weapon free from him, and fired more freezing bullets at Build, knocking him to the ground.   
  
"Not bad, Build," Meta Bolt said, as he tapped the weapon's barrel against his shoulder. "You're a lot better than I thought you were. However, this is my victory." 

Meta Bolt pulled out a Fullbottle of his own. It had the unmistakable silver image of a spanner on top of a light purple bottle, with a silver cap. Meta Bolt shook his Fullbottle, and inserted it into his weapon, and spun the valve once more. " **Devil Steam! S** **panner! Steam Shot! Spanner!** "

"Like hell it is!" Build said, cranking the Build Driver's handle furiously. " **Ready, go! Vortex Finish!** " 

Meta Bolt fired a large energy beam in the shape of a spanner, which splintered into smaller ones that started to home in on Build. Build pointed the Long Range Cleaner at Meta Bolt, firing the ice that was jammed into it at the spanner bullets. The resulting explosions kicked up a giant cloud of smoke and dust, and when the air cleared, Build had disappeared, having used the explosion to mask his escape. 

"Hm, smart move, using the ice I stuffed his weapon with to counter my attack," Meta Bolt said, sneeringly. "Still, he's got a long ways to go before he's really useful..."

* * *

Sento scowled as he ran. He couldn't believe it. He blew his chance to find out who he is, and what was going on with the Smash experiments. He didn't even find out the name of the organization behind all this. He only knew about one member. One member. And he said coworkers, clearly referencing the bat man and cobra man. And if they're anything like Meta Bolt, they're bound to be extremely skilled and powerful. 

Once he made sure that he was far enough away that Meta Bolt couldn't have followed him, he leaned against the wall, and slammed his fist against it in frustration. He checked his phone to see if All Might or Izuku sent him a message, before realizing he never traded numbers with either of them. "Man, I'm really off my game today..."

"There you are, Mr. Kiryu!" 

Sento turned around, and saw All Might (in his skinny form) and Izuku jogging towards him. "Thank goodness we found you! All Might left the girl at a police station, and we headed back as soon as we could, but you and Meta Bolt were gone! What happened?" 

"... I lost," Sento admitted, shaking his head. "Meta Bolt was a lot stronger than I anticipated, and all I could do was escape. He's still out there, no doubt planning to keep turning people into Smashes."

He slammed his fist against the wall again, scowling. "Stupid! I had our answers in front of me, and I couldn't do anything to get them!" 

"Hey, it's alright, Mr. Kiryu," All Might said, giving him a reassuring pat on the shoulder. "There will always be more chances to figure out things. Why, you got me and young Midoriya helping you out! So we're bound to be able to get answers again soon."

Sento took a deep breath, and sighed. They were right. He's only been at this for a while, so there's still a lot of time to solve this mystery. "You wanted to know how I got my hands on this tech, right? Well, I figure it'd be best if I took you to the man himself. That, and I'm famished. I'll treat you to dinner at the place I live at, since he's the one who's been housing me, too."

"That sounds fantastic, but can we go get the truck? We left it back there, and it's a rental..." 

* * *

"Bolt, what were you thinking?" Rogue said, as he rapped his fingers on the armrest of his chair. "I already made it clear, don't recklessly use the Transteam Gun's rifle mode for testing Hazard Levels. Not only that, you chose to engage with the Kamen Rider, as well as All Might. Why?"

"Like I said before, I wanted to test to see how far Build's progress has been going along, and what better way than to fight him?" Bolt said, flippantly. "While it's definitely enough to fight a mindless Smash and the average Guardian, he's no match for a Transteam Gun user. As for All Might, well, he seemed more concerned about taking those kids out of the way, so I didn't bother going after him outside of having the Guardians shot at them for a bit."

"Hm, a fair assessment," Rogue said, as he stroked the chin of his helmet. "Still, you're becoming far too careless in your approach after finishing the modifications for the Transteam Gun's rifle mode. I'm putting you on the bench until you learn more restraint."

"Sir Night Rogue, Sir Meta Bolt, if I may interject?"

Bolt and Rogue turned to face one of their Nebula Chamber scientists, who had finished cleaning up it up. "I feel like... calling it the "Transteam Gun's rifle mode" is a bit of a mouthful. Why not shorten it to something simple, like the Steam Rifle?"

"... Who are you to suggest anything?" Rogue said sharply, almost glowering at the scientist who began to back away in fear. "Especially as something as trivial as a name?"  
  
"I think it's an excellent name," a new voice interjected, one that was far more casual in tone than either Bolt's or Rogue's. They turned to face their third member, who, like them, was dressed in a leather-like undersuit, though his was red. His gunmetal armor pipes formed a muffler-like collar around his head, with a green cobra insignia on his chest, and his green visor matching it. "Besides, the 'Transteam Gun's rifle mode' is a mouthful."

"Stalk..." Rogue said, turning to his fellow leader. "Of what do I owe the pleasure of seeing you?"  
  
"Just checking up on things. Gotta say, I'm impressed, Bolt. You really outdid yourself on improving the Steam Blade's Nebula Gas injection capability by giving it range. To think, we can now just fire a gas bullet and bam! Instant Smash."

"Need I remind you that the Smash are not our final objective?" Rogue said, crossed. 

"Yea, yea. Speaking of which, we should slow down on the whole experimentation thing for a while, since we're starting to catch the attention of the media. Orders from our good sponsors," Stalk said, patting Rogue on the shoulder, who pushed his hand away. "Or at least be more discreet." 

"Hmph, fine. That does line up with my order to Bolt to stay put, not to mention give the scientists time to recalculate and modify the Nebula Chamber so we can use it on mutant-types more easily. The Nebula Chamber's door is getting cracked a bit," Rogue said, as he inspected the top of the Nebula Chamber. "Can't be too careful... Since you finished your modifications with the, um, Steam Rifle, I suppose I'll put you in charge of it for now."  
  
"Fine," Bolt said, crossing his arms. "Anything for Faust, I suppose."

"Well, if that's settled, I should get going," Stalk said, dusting off his hands. "Keep up the good work, you two. After all, there's a big future ahead for us all."

Stalk laughed as he walked off, leaving his two compatriots to stew in their thoughts. 

**Notes for the Chapter:**

> \- So while for the tags I'm using the versions of the names where they have a "u" after "o/u", I'm gonna just omit that entirely in the fanfic itself. So instead of Ryuuga Banjou, it's Ryuga Banjo. And yes, I'm also gonna use "first name last name" instead of "last name first name", too.  
> \- Sorry, but I'm gonna be using the English versions of the Fullbottle names, as well as "Transform" instead of "Henshin", if only to keep the fanfic as easy to read as possible.  
> \- While the Kamen Riders are transformed, I'm going to only refer to them as their Kamen Rider name and not their regular name to establish it as an identity they take up. Now this won't be the case when they transform for the first time or when the narrative hasn't revealed it yet, like how Sento was only ever referred to as "the Kamen Rider" before he revealed his name as Build.  
> \- A thing I'm changing is gonna be the stickers/labels on the caps. For the most part, they're just gonna be the Build symbol with no letters to hint at what the Best Match is. While that's good for a toyline, it kiiiinda makes it silly how Sento can't figure out what the Best Matches are when the answers are sorta staring in his face.  
> \- Relating to the Fullbottles, they're all going to be the same in color scheme. I'm gonna make the "Hokuto" and "Seito" Fullbottles solid colors instead of them being the "colored image only", since in this fanfic, they all need to be collected instead of only the Touto ones. Nothing else is changed about them, though. They're still the same shapes as they are officially.  
> \- Mild Spoilers for those unfamiliar with Kamen Rider Build: Something I realized I should've clarified last time, I'm gonna be replacing two Best Matches. One is MerryChristmas with F1Saurus, for obvious reasons, and PenguinSkater with CrocodiCon, since for whatever reason that was never an "official" Best Match despite the existence of the Crocodile Crack Fullbottle and the Gear Remocon, so I wanted to make a better fit, and as cool and fun of an idea a skateboarding penguin is, I feel like is one of the Best Matches that's easy to replace.


	3. Chapter 3

**Summary for the Chapter:**

> In which old friends reconnect after a few years, Bakugo continues to be the butt of everything, and the Best Match meets.

**Notes for the Chapter:**

> Sento Kiryu: Last time on "Building a Hero!", the genius scientist Sento Kiryu met the Number One Hero All Might and his secret apprentice Izuku Midoriya after saving another Smash victim. Together the three investigate where Midoriya was found after his kidnapping when they were attacked by another Smash. After using a new Best Match, the team of unlikely allies found themselves confronted by the spanner man of the organization behind the Smash incidents, Meta Bolt!
> 
> Izuku Midoriya: What are you doing, Mr. Kiryu?
> 
> SK: The chapter recap, gotta remind people about what happened in case they didn't read the previous one. 
> 
> IM: I feel like that's a bit of a stretch, considering that they could've just finished reading the previous one...
> 
> All Might: HAHAHAHA! Don't sweat the details, my boy! A recap is always an excellent addition to a story in case viewers and readers have missed a chapter! Not to mention bring some much needed levity! 
> 
> SK: See, All Might gets it. Plus, it gives us a way to entertain our audience!
> 
> AM: The dastardly detestable devious devil of a scientist Meta Bolt proved to be a much tougher foe than the courageously cunning Kamen Rider Build, no doubt in part to having experience in fighting while Mr. Kiryu had only been the Kamen Rider for a few months at best!
> 
> SK: Well, that's true, but you didn't need to say it like that... 
> 
> AM: And despite my own best intentions, I was unable to provide much help myself, due to the nature of Mr. Kiryu's Build Driver being the only thing capable of extracting the Smash essence, as well as needing to evacuate young Midoriya and the second Smash victim! 
> 
> IM: Speaking of which, can you make more Build Drivers for All Might and I? We could probably help you more if you did that. I mean, of course when I have my license and all.
> 
> SK: Well, that depends on your Hazard Levels.
> 
> IM: What's a Hazard Level?
> 
> SK: We'll find out, on this chapter of "Building a Hero!"

* * *

All Might and Izuku followed Sento down an alleyway to a small unassuming closed cafe. It was barely noticeable, with only a small sign with the name "cafe nascita" standing outside its door revealing its presence. The only way anyone would know about it is if they purposefully knew where it was.

"I didn't think there'd be a cafe down here," Izuku said, as Sento opened the door. "Doesn't seem like it'd get a lot of traffic here..." 

"Eh, that's why the Owner's got a second job at a different cafe. This place is more of a, well, private party cafe?" Sento said, scratching his head. "Then again, we don't even get parties here... probably for the best." 

As All Might closed the door behind them, Sento went behind the counter, and opened the minifridge behind it. "Hey Owner, I got a couple guests over."  
  
"What!?" a voice said, coming out of the minifridge. All Might and Izuku peered over the counter, and saw that the minifridge had a secret passage in it, leading to a stairwell. "Why are you telling me this through the entrance, it's supposed to be secret!"  
  
"Well, they kinda know that I'm Build, too."  
  
"What!? Why did you tell them!?" 

"They're important leads to what happened with me, come on, you gotta meet them."

"Fine, but if I don't like them, I swear, we're gonna have to do a disappearing act and move to a new place. And just when I was getting comfortable here, too..."

Izuku and All Might watched as a man emerged from the secret passage. He was just a bit taller than Sento, though his hat might've been giving him an inch or two over him. Tiny glasses rested on the bridge of his nose, and over his clothes he wore a green apron. For some reason, he looked familiar to Izuku, like he's seen him before. "Seriously Sento, this could really be bad news for- Toshinori!?"  
  
"Souichi!?" All Might said, caught off guard. " _You're_ the Kamen Rider's beneficiary!?" 

Izuku and Sento stared at the two, confused. All Might's personal life was a super secret, and he kept it that way in a lot of interviews (in no part to avoid having potential villains coming after his loved ones). Also, it seemed that despite the Owner's own cheerfulness in seeing an old friend, All Might seemed... far more apprehensive and serious.   
  
"Mr. Kiryu's boss knows All Might personally!?" Izuku thought, as he tried to process the information.

"You two know each other?" Sento said, quirking an eyebrow as he vocalized Izuku's thoughts. "How?"

"Me and Toshinori go way back! We were best buds since our high school days in U.A.! Well, at least before I dropped out when I realized heroism wasn't what I wanted to do. So how's being the Number One Hero, Toshi? Seems like it's kinda straining you bit, since you're all skinny right now. Let me fix you up something-"

"I need to talk to you. In private, Souichi," All Might said, firmly. "Is there anywhere we can do that?"

"Oh, uh, there's the kitchen's supply closet. But I think Misora would want to say hi to you, first."

"Lil Misora is here?" All Might said, his face softening. 

"Yea, hold on. Misora!" Souichi called into the minifridge's secret entrance. "There's an old friend who wants to see you!" 

"Ugh, coming..." a tired voice replied, small footsteps following it. A short girl just a little taller than Izuku came out of the minifridge, with short hair and a palm tree-like ponytail on top of her head. She was dressed in pajamas and had a golden bracelet on her right wrist. "Who'd the heck would I know- Uncle Toshi!" 

"HAHAHA, why, Lil Misora! You've grown!" All Might said, having instantaneously changed into his muscle form before Misora had finished climbing up the stairs, much to the shock of the other three. "You've become a fine young lady, if I can say so myself!"

The girl practically launched herself onto All Might, giving him the biggest hug she could muster. "It's been forever, Uncle Toshi! What're you doing here? Dad said that you've been too busy to visit since you're All Might and all!" 

"Hahaha, well, truth be told, I'm here because your friend Mr. Kiryu told me his big secret," All Might said, causing Misora's smile to turn upside down. 

"What!? Sento you idiot!" Misora said, letting go of All Might and slapping Sento upright in the head. "What were you thinking!? Even if it's Uncle Toshi, that was a stupid move!"

"I know, I know, it was risky, but I thought I could trust him!" Sento said, raising his hands. "After all, his apprentice Izuku got kidnapped by the organization behind the Smash incidents and my amnesia!" 

"What? Really?" Misora said, finally paying attention to Izuku, who froze up. "Uncle Toshi's got an apprentice?"

"Well, what can I say?" All Might said, with a mighty laugh. "I'm feeling the years on me! And there's never a wrong time to start working on the next generation of heroes!"

"H-h-hi!" Izuku said, standing straight and shooting out a hand to shake with. "I-I'm Izuku Midoriya! Pleased to meet you!" 

"... Misora Isurugi," Misora said, as she shook his hand. "Pleasure to meet you, too," she added, with a small smile. 

"Wait... 'Isurugi'? Like, as in the astronaut?" Izuku said, his eyes widening. He shot a look at Souichi, now realizing where he recognized him from. "You're the astronaut that caused the Skywall Incident!" 

"What!?" Sento said, his eyes practically bulging out of his head. 

"Oh wow, how did you figure that out?" Souichi said, raising an eyebrow. "Sento never figured that out on his own."

"I... I watched the video of the celebration ceremony a lot as a kid," Izuku said, looking to the ground. "It was one of the things I'd watch a lot, besides All Might's debut..." 

"Well, I was keeping that a secret from Sento until he was ready to learn it, but I guess that's out in the open now," Souichi said, causing Izuku to freeze up. "Let's get to that private conversation now, Toshi."

"Hahaha! Agreed, Souichi!" All Might said, though the laugh seemed a little more forced than usual. With that, the two old friends disappeared into the kitchen, leaving the three younger people in the front. Izuku looked towards Sento, who had crossed his arms and tapped his left foot angrily, frowning. Misora sighed, and shook her head.

"Thanks for that, Midoriya," she said, a little sarcastically. 

"When was he gonna tell me?" Sento said, crossed. "I thought he trusted me." 

"Why did your father do that?" Izuku asked, looking at Misora. "I mean, he doesn't seem like the person who'd cause a disaster like that..."

"He isn't," Misora said, firmly. "I don't know much myself about what happened, 'cuz when it happened, I got into a coma, and when I came out of it, I had this bracelet on," she said, pointing to her wrist. "If you wanna know more, just ask him instead." 

"Don't worry, we will," Sento said, sighing. "Honestly, I don't think he's a bad person. He's probably done a lot of things, but I doubt he's evil. I mean, he provided me with the Build Driver and the Fullbottles to save people with."

"Yea, dad's a lot of things, but he isn't evil," Misora said, confidently. "I'm sure he and Uncle Toshi are just catching up with each other, since they haven't seen each other in years."

* * *

"Is what you said just now true, Souichi?" All Might said, his face lowered. He had turned back into his skinny form, having released it the moment they were out of view from Misora and the others. He couldn't let her see him like this. He was the invincible Number One Hero, the Symbol of Peace, and most importantly of all, Uncle Toshi. He couldn't disappoint her, not like this. 

"Yea, it is," Souichi said, scratching the back of his head. "But please don't tell Sento or that Izuku kid. At least not yet. You already saw how they reacted to me being the astronaut, I don't need them to freak out more. I already have a lot of regrets, just like you know. Still, that's some pretty heavy stuff you've been going through, too. Are you really losing your Quirk?"

"... Yes," All Might said, half-truthfully. "Doctors said it's probably some sort of birth defect that they didn't detect when I was younger and not overdoing things as much yet. The more I work and get older, the less effective my Quirk is. I'm at the point where I can only really do three hours of real work a day. Still, I'm surprised that you recognized me in this form, since we haven't seen each other in years, Souichi."

"What can I say? You're one of my best friends, Toshi, I bet I can recognize you a mile away while you're in a dress singing opera," Souichi said, giving All Might a light punch. The two chuckled. "I missed this, you know, just talking. Seriously, you might be the Number One Hero, but it wouldn't hurt to check up once in a while."

"Yea, I'm sorry about that," All Might said. "Can't be too careful with keeping everything a secret, since there are villains out there that would do anything to hurt me and the people I love."

"I hear you on that, Toshi," Souichi said, sighing. "Hope that Sento isn't too upset about what's happened."

* * *

"Seriously, you want a Build Driver, too?" Sento said, looking at Izuku from his work bench. He and Misora figured that since Izuku knew who he was now, that they'd let them in to the Build Shop. It was a small basement-like area, with a "living room" where the stairway was, which had a small kitchen area, a couch and TV, and a small hallway that led to some bedrooms that Sento and Misora use (Souichi slept in the "master room" above the cafe. And then there was the workshop where Sento made his gear, with some strange big metal box that was sitting against the back wall. Misora had walked into it with the two bottles that Sento had gotten from the Smashes earlier, muttering something about having to get paid by Sento soon. 

"N-not for me! For All Might! I-I mean, you saw how he reacted earlier when that Smash attacked," Izuku said, sadly. "He was so frustrated that he couldn't save that girl while you fought... I figured that, well, he could do so much more if he could become Build, too!"

"That's some sweet sentiment you have, Izuku, but not realistic. For one, I really don't have too much resources and materials to make more stuff. It's tough getting that, especially with the small salary I'm making at the Institute and whatever the Owner's doing. Second, you have to have a Hazard Level, and considering that All Might hasn't mentioned being experimented on, I don't think he's got one."

"A Hazard Level?" 

"It's a measure of a person's resistance to whatever gas those guys have been using," Sento said, getting up to draw on a glass board that was hanging from one of the rafters in the workshop. "I don't really know the specifics of how they work outside of that yet, though. But you need a certain level to be able to use them. Otherwise you'd get shocked if you're not at the right threshold. Or it just doesn't work at all, which is much more preferable than the shocking." 

"Oh... Wait, so does that mean I have a Hazard Level?" Izuku said, pointing to himself. "They sprayed gas on me, too, so does that mean I can become a Build?"

"Well, you can become a Kamen Rider, yes. Not Build. I'd like us to have different names, mind you. But you do bring up a good point about having a Hazard Level," Sento said, as he pulled out a Fullbottle that had a Japanese rhinoceros beetle imprinted on it, and tossed it to Izuku. "Here, take this, it's the Beetle Fullbottle."

"W-what? Why? Don't you need it?" Izuku said, as he felt each groove and ridge of the Fullbottle. 

"Eh, not right now. I already tried pairing Beetle with the other Fullbottles I have, and none of them are its Best Match. Plus, you can still use them without the Build Driver. Observe," Sento replied, taking out his Rabbit Fullbottle. He gave it a shake, and twisted its cap. In the blink of an eye, he moved out of his chair and right next to Izuku, startling him. "By simply shaking the Fullbottles, you activate the abilities that they grant. At least, to a degree. The Build Driver and the other tech are what really allows you to utilize them to their fullest potential, but if you just need a boost, you can just shake it. Go ahead, try it."

Izuku stared at the Fullbottle, and kept examining it. As he moved to shake it, the strange metal box made a loud echoing ding suddenly, startling him. Sento, on the other hand, grinned manically, as a cowlick sprung up from his head. "Finally!"

He rushed to the metal box, and opened a microwave-like door on it, revealing two Fullbottles. One was brown and had the shape of a gorilla as its image (no doubt from the Strong Smash victim), while the other one was dark gray and had the shape of a simplistic robot as its image (definitely from the Claw Smash victim). "Ooooh, Gorilla _and_ Robot? I feel a Best Match coming up with this! Thanks, Misora!"

Sento walked off, and inserted the new Fullbottles into the Build Driver. " **Gorilla! Robot!** "

"What? They're not? Aaaaaw!" Sento said, bemoaning the disappointing result. Misora, on the other hand, opened the metal box's door, and walked off to the couch, muttering, "Tired... Sleepy... Want my money, Sento...", and then instantly passed out. Izuku just watched the entire thing, baffled. 

"So does Misora have a Quirk that lets her purify the Smash essences?" Izuku asked, as he kept shifting his stare from her, to Sento, and to the metal box. 

"Huh? Oh, no it doesn't. Her Quirk's Idol Smile, it enhances her cute factor and gives her a great singing voice. Not to much to say about its weaknesses, really, besides it not working on everyone."

* * *

**_Misora Isurugi! Quirk, Idol Smile! It's... exactly as Sento says._ **

* * *

"R-really? Then how does she do it?" 

"It's... complicated. From what I gathered and tested so far, it seems like the source of her purification powers come from the bracelet. It's hard to really pinpoint how it works, but I have at least figured out how to make it less of a strain with the Purification Chamber. When we started, she'd pass out for days, now it's just a couple hours. Hoping to eventually make it so that it doesn't wear her out at all." 

"But enough about that, let's see you try that Fullbottle out!" Sento said, as they returned their attention to the Beetle Fullbottle. Izuku looked at the Fullbottle hesitantly, but as he started to give it a good shake, his phone started ringing. 

"Oh, um, hello mom?" Izuku said, picking up the phone and instantly answering it. "Sorry, but training is taking a little more time than I thought. What? Oh, don't worry, I'll be home soon! You can go ahead and start cooking now, I'll be there in about 30 minutes!" 

"Sorry Sento, I gotta go," Izuku said, handing the Fullbottle over. "I'll come back here after I'm finishing doing All Might's training to start training here?" 

"That sounds like a plan. Give me your phone, I'll give you my number," Sento said, taking Izuku's phone and dialing his number. "That way you can message me when you need to." 

Izuku nodded, and walked up the stairs, coming across All Might and Souichi, who had finished talking in the kitchen. 

"Oh, sorry All Might, but I have to go, we went over our training time, and my mom got worried," Izuku explained. 

"That's fine. A lot happened today, so we can take it easy for the moment," All Might said, waving it off. "I just expect to see you first thing tomorrow morning, so we can make up for lost time." 

"That's fine with me!" Izuku said, beaming as they walked out, with Souichi waving them off. Whatever happened between All Might and Souichi, it seemed like they managed to talk it out. 

* * *

The next day at school, Izuku felt like he could pass out. All Might wasn't kidding when they said that they'd compensate for missing out on training. He had to work over time to get in what he missed. Still, he knew he had to stay awake, since he needed to keep his grades up and all. 

"Look, there's Bakugo," someone muttered, as Bakugo entered the classroom. People froze as they watched him walk to his desk, and sat down quietly. As people started to mutter, a couple wise guys looked at each other, and smiled smugly.

"Hey, Bakugo! Think fast!" one of them said, throwing a rubber ball. To their horror, Bakugo caught the ball, and it exploded in his hand. "O-o-oh, n-nice catch, Bakugo! I-I-I knew you could-"

"That's right, you two-bits! I got my Quirk back!" he said, his scowl turning into a twisted grin. "And it's better than ever! I feel like my explosions are five times as strong as they were before!"

"T-that's great, Bakugo!"

"Yea, I knew you could get over it!" 

"Y-you're the best!" 

"Shove it, you extras! Don't think I'd forgive you little shits for what you've done yesterday! I'm not a little fucking pushover!" he said, getting up from his desk. He threw the ball as hard as he could without his Quirk, watching it slam itself right into the ball thrower's face, knocking him right out of the chair. "It's not just my Quirk that's stronger! I feel like I could take on twenty, no, FIFTY villains with just a pinky!"

"S-sorry about that, Bakugo!" the ball thrower said, holding his now very bruised cheek. "I promise, it won't happen again!" 

"It better not!" he said, kicking the ball thrower's desk. "Because I'm never losing my Quirk aGAAAAAIN!"

To everyone's shock (especially Bakugo's), when he kicked the desk, it exploded, much like how he could make explosions with his hands. But with his foot. The explosion launched the desk right through the classroom's hallway windows, shattering them. Bakugo himself was launched the other way, having been thrown completely off-balanced thanks to standing on one leg while he had kicked. He landed against the desks behind him, his right shoe was gone, having followed the desk after he had kicked it. 

"What the hell!?"

"When can Bakugo make explosions with his feet!?"

"He wasn't kidding when he said that his Quirk's gotten stronger!" 

"Dang, if I had known getting turned into a monster like that would boost my Quirk's power, I would've done it twelve times now!" 

Izuku just stared at what had just unfolded. He grabbed his phone out of his bag, and sent a message to Sento as fast as he could. 

* * *

**all_might_jr:** Mr. Kiryu?

 **the_genius_scientist:** Oh hey Midoriya. Should've figured it was you by the name.

 **all_might_jr:** Yea, I... plan on changing it. But enough about it. What happens to your Quirk when it returns?

 **the_genius_scientist:** It comes back like, five times stronger, and it mutates just a bit. Why?

 **all_might_jr:** My classmate just kicked a desk and it exploded from his feet. He couldn't do that before. 

**the_genius_scientist** **:** Oh right, explodey boy. I should've figured. Well, if he wanted to be a hero, he shouldn't worry. It's a permanent power-up. 

**all_might_jr:** Really?

 **the_genius_scientist:** Yep. 

**the_genius_scientist:** Oh, I never mentioned that, did I?

* * *

Izuku sweated. So after temporary Quirk loss was a permanent Quirk power-up? That was insane. Is that why he became stronger than he was before? Izuku grinned slightly, glad that All Might's suggestion about it being temporary wasn't true. 

"What's going on!?" a teacher said, staring through the broken window at the chattering class. "Who did this!?" 

"It was Bakugo!" the ball thrower said, pointing at him. 

"Yea, after you provoked him, idiot!" his friend said, selling him out. 

"Way to go getting yourself into a fight with the guy who can make things explode!" 

"It's all your fault!" 

"Quiet! I don't care who's fault it is," the teacher said, rubbing his temples. "I want the two of you to stand outside, while I get the principal to talk about how to discipline the both of you!"

Bakugo grumbled and did as he was told reluctantly, while the ball thrower started tearing up, realizing that his parents were no doubt going to be furious. Izuku just sat there, dumbfounded about it all. He really hoped that that was all the excitement he was going to get today. 

* * *

The entire day after that was, surprisingly, uneventful after that. And so were the next eight months, in fact. Outside of six minor Smash attacks that occurred in secluded areas (which gave Sento the Pyramid, Remote Control, Dog, TV, Smartphone, and Giraffe Fullbottles), Izuku's time was spent more on training and working with Sento on learning how to use the Fullbottles and what they can do, which he's been listing in a new personal "Secret Rider Files" journal that he kept at the Build Shop so that no one would notice him writing in it in public. It was Sunday, and they've been testing the effects of the Fullbottles while untransformed so that Izuku could record them himself. 

"Alright, Midoriya, let's try using the Smartphone Fullbottle," Sento said, as he typed behind his computer. Izuku nodded, giving the bottle a little shake and twisting its cap open. When he did, he saw a small holographic-like screen being projected out of the cap, which resembled a smartphone screen. He pressed what appeared to be the "call button", and dialed in Sento's phone number. Sento's phone ringed, and he picked it up. "Hello?"

"Oh, so the Smartphone Fullbottle can function as a phone! Makes sense, though it really just makes me wonder why use it instead of a regular one..." Izuku muttered, as he closed the cap and went to his Secret Rider Files journal to write in it, getting to the page about Fullbottles effects. 

"They can't all be combat-oriented, you know," Sento said, shrugging. "Plus, if you lose or break your phone, this could be pretty useful, since Fullbottles can't be broken."

"True," Izuku said, as he added an addendum to the Smartphone Fullbottle's effects. "Still, I don't think any of them could beat the Beetle Fullbottle and its drill punches. It definitely compliments my super strength Quirk!" 

All Might smiled as he watched Izuku and Sento experiment with the Fullbottles. Misora had gone to sleep in her bedroom (allowing All Might to be in his skinny form, since he didn't want to disappoint her with how he looked now), and Souichi had gone off to his second job. While the investigation in the organization behind the Smash incidents hadn't gone anywhere recently, they were at least making progress with Izuku's training. When he was told that the super strength and speed that the experimentation done on Izuku was permanent, he was relieved and worried at the same time, since that meant that the other people that were experimented on were must be suffering from a sudden burst in their power, too. But at the same time, it allowed Izuku to breeze through the training regiment he had planned, to the point where he received One for All a couple weeks ago, much sooner than anticipated. Granted, Izuku's first usage left his right arm broken (Recovery Girl wasn't too pleased about having to come to the beach after work hours), so they had to still train to refine Izuku's control. 

"Indeed, these Fullbottles are quite useful. But I doubt that you'd be allowed to use them in the practical for U.A., or at all in general," All Might said, chuckling a bit. "Can't say they'd be too welcomed to a 'violent vigilante's' technology."

"Hey, Build is not a violent vigilante!" Sento said, feigning hurt. "He's a hero of justice! Just one without a license, that's all." 

Izuku chuckled as he read over his notes. While it was true that initially All Might wasn't too fond of the idea of working with Build, due to his "technically illegal activities", they did end up seeing eye to eye eventually, All Might even admitting that the government probably wouldn't be able to properly give Sento a hero license in spite of how helpful his technology was. Still, that didn't mean that Build could ever be seen working with All Might in public, so the two work are forced to work as far apart as they could. 

"Still, I could probably work this stuff into my own gear when I'm out of U.A. and college. Discreetly, of course," Izuku added, looking at his notes. "Maybe I could become an pro hero Kamen Rider."

"Speaking of which, you want to check your Hazard Level? It's been a while since we've checked," Sento said, bringing his phone out. He scrolled through the apps, and pressed on the one marked "HL Indicator". He pointed it at Izuku, and whistled. "Wow, 2.26, you've risen quite a bit. If this keeps up, you probably can use a Build Driver!"

"Really?" Izuku said. "I mean, that would be great, but I need to be a pro hero first in order to justify it."

"Don't worry about it. As much as the law is necessary to follow and protect, sometimes heroes do need to stick their noses where they shouldn't in order to help people," All Might said, reassuring Izuku. "Besides, some vigilantes I've seen end up becoming pro heroes themselves! Though it's definitely not a reliable road to take on the path of heroism."

"Don't worry about it, you'll need a Hazard Level of 3 at least to be able to use it. With the rate you're raising, it won't be too soon," Sento said, returning his attention to his computer. Izuku looked at the clock, and realized that it was getting late. "Oh, I should get home soon," he said, as he returned the Smartphone Fullbottle to Sento. "I gotta rest before starting up training again."

"Indeed, we have to refine your technique, young Midoriya," All Might said. The two of them waved goodbye as they walked up the stairs, leaving Sento to work alone again. 

"Let's see... should I start finish working on the Gatling Fullbottle's gun?" he said to himself, as he glanced over to the unfinished weapon on the work bench behind him. "Still need to find that Best Match, though..." 

* * *

The next day, Sento was hard at work over reconducting experiments the Institute had done in the past. While initially just an intern, he's been quickly moving up in positions thanks to his intelligence, and noticing some elements that previous experiments hadn't taken in account for, and decided to redo them to see how the results have changed. So far, a great deal of them had been drastically different.

"Mr. Kiryu."

"Hm?"

Sento turned around, and saw the bespectacled Nariaki Utsumi, the aide to Gentoku Himuro, the current head of the Institute and Prime Minister Taizan Himuro's son, approaching him. "What can I do for you, Utsumi?"

"In regards to your work in reexamining past experiments and your input on current ones, Mr. Himuro has decided that the best course of action for you is to be moved into the Pandora Box Observation and Testing Team," Utsumi explained curtly, pushing his glasses up his face. "Of course, we expect you to be able to-"

"I get to work with the Pandora Box!?" Sento said, grinning widely as a cowlick sprung up from his hair. "I'll go over there right now!" 

Utsumi scoffed, having gotten used to Sento's rather... strong enthusiasm for science. He watched as the man rushed out of the room, leaving him and his fellow scientists behind. 

"Finally, he's gone."

"I couldn't stand him being so smug."

"He wouldn't even be here without his super intelligence Quirk."

"Yea, I bet he'd be nothing without it." 

* * *

"The Institute's research on the Pandora Box has been relatively... fruitful. While we haven't cracked the code of how it created the Skywall, and we've yet to figure out its purpose, and what it's made of, we've at least figured out that it's capable of generating a great deal of energy," Gentoku Himuro said, stroking his well-trimmed goatee. 

"Hm, I see," Sawa Takigawa, the reporter, said, writing down in her notes. "So how much longer do you think that will take? And will we be able to reverse the Skywall and reunite the countries in the process?"

"Who knows... we've been at this for ten years, and it's only recently we've figured out its energy generating capabilities," Gentoku answered, as they walked over to the observation deck to where the Pandora Box was being stored. It was encased in a large metal box with only a few small windows that allowed people to peer through. Guards were in place to keep the Box safe, while a team of scientists walked around, writing down notes and typing into laptops. 

Suddenly, to Sawa's surprise, a man wearing a large brown overcoat rushed into the room, looking into the chamber containing the Pandora Box, chattering excitedly to the scientists who looked a bit too exasperated at seeing him enter. Even the guards seemed to be a little annoyed with him. "Oh, seems like my aide Utsumi finally told our newest scientist that he was being moved to the Pandora Box team." 

"Your newest scientist? I didn't think someone like that would be put on such an important team like that," Sawa said, watching as the excited man sit himself down next to a plain-looking fellow and a man with a bird-head and glasses. 

"He's unlike anyone we've ever seen," Gentoku said. "At least, not since Katsuragi. Either way, he's shown a remarkable intelligence, which I thought we were wasting unlike my fellow board members, so I had him moved to the team in spite of his relatively recent employment." 

"I see... Well, Mr. Himuro, I think we're almost done here," Sawa said, before she took out a few pictures, which were of the Kamen Rider and a few Smashes. "I just need to ask you your opinion on the Kamen Rider, and his activities towards defeating what people are calling "Smashes" online. It seems like technology like his would be something that the Institute would be interested in."

"Hm... that information is confidential at the moment, unfortunately," Gentoku said, before wrapping an arm around her shoulder. "But I think we could talk it over, say, a long night interview after dinner and at a hotel?"

The two walked for a bit, before Sawa managed to process what he just said and suggested.

" ** _What!?_** "

* * *

"Ugh, I can't believe the gall of that guy!" Sawa said, complaining to her boss on the phone as she walked home. It was evening, and she was alone in a park. "Just because he's super important doesn't mean he can just do that! Hm? Is the offer still on the table!? Seriously!? No, of course not! What, just because I haven't had a good story in months doesn't mean I can't have integrity!" 

As she hung up on her phone, something tapped on her shoulder. She turned around, and came face to face with a strange white-colored being, with white-to-blue gradient spines coming off its torso and arms. Its head was airplane-like, with two blue eyes glowing out of it. 

"Smash!" she cried out, trying to take a picture of it with her phone. The Smash smacked it away quickly. "Hey, I still had minutes on that!"

The Smash slapped her aside, knocking her to the ground. She tried to get back up, but the Smash was approaching her, drawing out a long needle-like claw from its index finger. She closed her eyes, and hoped that someone would come help her. 

"Hold up a second!" 

She opened her eyes. A red-and-blue armored man had appeared almost out of nowhere, and grabbed the Smash's hand. He pulled the monster away, leading it as far away from Sawa as he could. Sawa followed them discreetly, hiding behind a tree in order to make sure she wasn't seen. The armored man was attacking it with a flurry of punches and kicks before summoning a drill-gun-sword contraption and striking the Smash with it. The man pulled out the red bottle in his belt and inserted it into his weapon, which announced, " **Ready, go! Vortex Break!** "

The man struck the Smash multiple times, as red energy swirled around the weapon's blade. With the final strike, the Smash exploded, knocking it against a tree. As it struggled to get back up, the man pulled out a clear bottle, and pointed it at the Smash. She watched as light particles flowed out of the Smash and into the bottle. When it was over, all that was left of the Smash was an unconscious man. The armored man looked around, finally giving Sawa a good look at his helmet's mismatched eyes. 

"Kamen Rider..." she said, in awe. 

* * *

"So you saved another person last night?" Izuku asked, as he and Sento watched the Purification Chamber, waiting for Misora to finish purifying the latest Fullbottle.

"Yep, this guy was a real pushover, though, unlike the other Smashes I've fought against," Sento said, a bit smugly. "Didn't even need a Vortex Finish to beat him, just a Vortex Break with the good ol' Drill Crusher." 

"Still, it's frustrating! We still haven't found Meta Bolt or the other members of the organization, and they're still managing to make Smashes," Izuku said, frowning. "It's just not fair, all we do is just react!"

"It isn't," All Might said, as he flipped through the news on the TV. "That's why we heroes must be vigilant and on constant watch, even when we're off hours."

"-Breaking news, the convicted murderer Ryuga Banjo has escaped prison and is on the run, the warden confirms," a newscaster said. All Might paused, and the three of them watched the channel, as it showed them the images of a brown-haired man with braids on the right side of his head, and showing footage of him having beaten up a small troop of Guardians. "Local police advise to stay in your homes or jobs while officers, Guardians, and pro heroes search the area to capture the convict. He was last seen-" 

"So he's escaped, huh..." All Might said, frowning as the newscaster revealed as much information as they possibly could. "Well, that doesn't matter. The proper authorities will take care of him. You should go home, young Midoriya. There's no doubt that your mother would be concerned if she saw this news herself."

"Alright All Might," Izuku said, getting up, but before they could go, the Purification Chamber dinged, signaling the Fullbottle's completion. Sento excitedly got up, and rushed to the Purification Chamber, and opened the microwave door. 

"Oh, so it's a hedgehog?" Sento said to himself, inspecting the white Fullbottle's hedgehog image. "That's probably a good indicator of what its powers are like... Go on ahead home, Midoriya, I got things covered here."

* * *

As All Might and Izuku drove off in All Might's car, they passed by an unusual scene. A small group of Guardians that were leading three teens away somewhere. One of them was a black-haired teen with sharp teeth, another was a horned girl with hoof-like feet, and the third was also a horned girl, but was pink with regular feet (from her hair to her skin). Something in All Might's gut made him remember the Claw Smash incident, and his worries were confirmed when the boy tried to fight the Guardians, but was subdued by them instead. 

"Wait right here, Midoriya..." All Might said, as he stopped the car. He got out, and discreetly followed the Guardians. Izuku, meanwhile, sat patiently, looking through his phone when he saw something running past the car. He looked up, and froze for a bit. It was the escaped convict, Ryuga Banjo. Izuku didn't know what to do; on the one hand, he needed to follow All Might's orders, and Ryuga Banjo was a murderer. On the other hand, Ryuga Banjo was a _murderer_ , and who knows how many people he'll hurt if no one stopped him. 

"Curse my hero complex..." Izuku muttered to himself, getting out of the car and following the convict as quickly but silently as he could. He sent a message to Sento, hoping that, while he wasn't a pro hero and therefore not really "eligible" to apprehend him, that he'd be at the very least willing to keep Ryuga Banjo at bay enough that actual pro heroes and officers can come and do so.

* * *

As All Might hid behind a pillar, he was infuriated at who he saw was at the center of this. There, leaning against a tree, was Meta Bolt, the scoundrel. There was no doubt that these Guardians were hijacked by him and his organization, and that he had found three new potential Smash victims. He stayed silent, and listened as Meta Bolt began to speak.

"Tch, took you long enough," Meta Bolt said, as the Guardians held the three captured teens. "You Guardians should've gotten them a lot sooner than this, since this is an emergency. Can't believe that not only did another subject slip through our grasp, but he broke the main Nebula Chamber, too. And just when I finished modifying it too..."

"The 'Nebula Chamber'? Sounds like one of the ways they turn people into Smashes," All Might thought, his fist clenching. 

"Who the heck are you!?" the pink girl asked, as she struggled against the Guardian's grasp. "Let us go!" 

"Yea!" the boy cried out, as his skin appeared to harden, but the Guardian holding him tightened its grasp, making him wince. "You're no man if you're just getting a bunch of Guardians to do your dirty work!" 

"You're just a _big bully_!" the horned girl said, inserting some English into her sentence. "A hero's gonna come and _beat the crap out of you_!" 

"Hmph, you all talk a big game," Meta Bolt said, almost as if he were bored, as he traced the edge of his weapon's blade with his finger. "Then again, I know you three are U.A. hopefuls, so I guess you'd have to have some grit."

"W-what!?"

"How did you that!? Wait, you were thinking of going to U.A., Ashido?"

" _Holy shit_!" 

"Doesn't really matter how I know," Meta Bolt muttered, shrugging. "Not like you're gonna really remember much about what's gonna happen."

"NOT SO FAST, VILLAINOUS SCUM!" All Might said, instantly changing into his muscle form and leaping into the air, landing a few of the Guardians that were standing at the back. "FOR I AM HERE!" 

"All Might!?"

"No way!"

"This day keeps getting _crazier and crazier_!" 

"Figures we'd meet again, All Might," Meta Bolt said, popping his neck. "Though it doesn't seem like you've got any backup with you today to save anyone."

"I don't need backup to handle villains like you!" All Might said, his signature smile replaced with a grimmer frown. "How dare you use the youth of today as your experimental fodder!" 

Meta Bolt simply chuckled, before firing his weapon at All Might. All Might avoided all of the bullets, reappearing right next to Meta Bolt before swinging a powerful punch towards Meta Bolt's gut. He moved out of the way, though the burst of wind that resulted from All Might's punch still knocked him off his feet.

"Hm, even without a Hazard Level, you're leagues above a Smash, All Might!" Meta Bolt said, getting up as fast as he could while spinning his weapon's valve. " **Devil Steam!** " "But let's see you take this!" 

Meta Bolt pulled the trigger three times, firing three gas bullets that flew towards All Might. All Might prepared himself to dodge the attack, but to his horror, the gas bullets suddenly changed course. He looked, and saw the gas strike all three of the teens straight in the chests. 

"Ugh, crap!" the boy said, as he tried to waft the gas away from them. "Don't breathe this stuff in-!" 

"Nonononono-" the pink girl said, panicking as the gas surrounded her. The horned girl meanwhile tried to hold her breath and lean away, to no avail. 

All Might watched as the cloud enveloped the three teens to his horror, before turning to Meta Bolt, while flames of rage burned in his eyes. 

"Wow, if looks could kill, you'd have won this fight, All Might," Meta Bolt said, chuckling as he pulled his weapon apart to form his gun and blade. "Did you really think we wouldn't have measures for things like this? There's no way that I'd win a straight fight, so why not make it a little more, unfair?"

"You bastard!" All Might said, grinding his teeth, struggling to keep cool. "How dare you bring children into this!" 

"Hmph, should you really be focusing on me, instead of them?" Meta Bolt replied, pointing to the three teens. All Might looked back, and his furious frown turned into a horrified one as the teens' transformations were complete.

Where the pink girl stood was now a Smash with yellow metal-like flesh, with hexagonal holes on her chest a like a beehive, and her hands had stinger-like fingertips. Her back had sharp wing-like protrusions that stuck out, and she had a bulbous bee-like butt with a large stinger. Her head had become smooth, with only two telescope-like eyes and two needle-like horns. The boy's transformed skin resembled polished stone, with triangular points coming out of his knuckles, elbows, and shoulders. Gem-like "stones" formed his pecs and abs, and his head had become a series of spikes clustered together, with two small yellow dots forming his eyes. The horned girl kept her horns, only now they branched into smaller and smaller horns like a deer, her face smooth and devoid of any markings besides two nostril-like holes and crack-like eyes. Her finger times covered in black hoof-like markings, as hard metal-like plating ran up and down her body. 

The three Smashes growled as they started to attack the Guardians around them, breaking them into pieces as All Might watched in horror. "You three," Meta Bolt commanded, as the three Smashes stopped rampaging and turned to face him, suddenly obedient. "Go find Ryuga Banjo and secure him until I can find you again."

"What? Ryuga Banjo?" All Might said, confused, before refocusing his attention. "Whatever you want with Ryuga Banjo, I won't let you use these teens for your nefarious purposes!" 

"Fine, but I think you'll want to stop them first before going after me," Meta Bolt said, holding his gun. "Well, what's it going to be, All Might? Me, or those Smashes?"

All Might shifted his glance between Meta Bolt and the Smashes, who had began running and leaping away in the distance. He growled, and ran off after the Smashes, knowing that while he'd be letting Meta Bolt go, the teens were the immediate victims and dangers that needed to be handled. 

"Just as expected," Meta Bolt said, as he swung his gun, forming a gas cloud that covered him. When it dispersed, he had disappeared, leaving no trace behind. 

* * *

"Dammit, where do I go now!?" Ryuga asked himself, looking around the empty industrial area, making sure he wasn't seen. Ryuga wasn't the smartest guy around, nor an especially lucky man; everything he had achieved in life he powered through. He became Breaker Box the Electrical Boxing Hero's sidekick through sheer grit, even with his lackluster grades and lackluster Quirk, became an esteemed pro boxer in his own right, and wanted to eventually start his own hero business. Life unfortunately has a funny way of throwing a lot of bad luck just as quickly. Breaker Box got caught fixing matches, but to avoid losing his license, Ryuga somehow ended up being the fall guy, which resulted in losing both _his_ hero and boxing licenses instead. So he was forced to go job-hunting, especially if he wanted to get his girlfriend Kasumi her medicines. When she said that someone came to her telling her that he had a job for him, he jumped at the chance, though he admittedly didn't know a thing about science. And that's when he found the guy, Takumi Katsuragi, dead on the ground, and he was arrested immediately at the scene of the crime. 

Now he got to add getting sleep powdered at the facility he was held at and waking up to being experimented on to that long list of bad luck. He didn't even know what the hell they were doing, just that he was in a weird glass box thing with green water, handcuffed, and had a weird mask on while they pumped white gas into the box. He did get a sudden burst of strength he didn't know he had, though, and broke the lid off while fighting off a bunch of the guys in white and the hijacked Guardians they had, and ran as far as he could, hiding everywhere he could find to avoid being caught. He just kept running and running, never looking back, at least until this very moment. He knew he couldn't keep it up forever, though, and that he'll end up getting caught eventually. 

As he struggled to think about what he could do, he heard something fall over nearby. He got himself into a boxing position, ready to swing his fists at whoever was there. "Show yourself!" he said, scanning the area for anyone he could find. "If you're one of those guys in white that messed with me, you're not taking me back without a fight!" 

There was silence for a few seconds, though Ryuga could've sworn he heard muttering. Then, from behind a wall of pipes, poked out a green-haired teen. "H-hi, um, Mr. Banjo?"

"A kid?" Ryuga said, raising his eyebrow. The teen didn't seem to be much older than Kasumi's youngest brother, but he could just be one of those guys who's Quirks made them super youthful for the rest of their lives, so he didn't lower his guard at all. "Well, whoever you are, you're not taking me to the police, or those guys in white! I didn't rig fights or kill that guy!" 

"I... was just passing by," the teen said, his grin nervous. "B-but you mentioned guys in white? D-do you know where they are?"

"Those jerks? No," Ryuga said, still on guard. "And I refuse to let them take me back there!"

"O-oh, um... well, I'm sorta like you, then! You see, I-"

The teen was interrupted by an engine revving, and a motorcyclist rushed past him and towards Ryuga. He barely had time to jump out of the way as the motorcyclist came to a stop. 

"Thank goodness you sent me that GPS location as soon as you could, Midoriya," the motorcyclist said, taking his helmet off. "I'll take care of him until an actual pro hero comes." 

"W-wait, Mr. Kiryu, you can't-" the teen said, panicking as he tried to figure out how to explain things.

"Don't worry, I won't be using my Quirk," the motorcyclist said, taking his helmet off. He pulled out a strange red bottle and shaking it. He twisted the cap open, and in an instant, he disappeared, only to reappear right next to Ryuga, who he tried to kick, but Ryuga blocked the kick and jumped back. 

"Oh, you want to fight!?" Ryuga said, cracking his knuckles. "Well buddy, you picked the wrong former pro hero boxer sidekick amateur science assistant to fight with!" 

"You... don't really need to list out everything that you are like that," the motorcyclist said, before getting punched in the side from Ryuga's right hook. "Ooow! Hey, that hurts!" 

Ryuga didn't listen, as he focused on solely throwing punches like he used to. The motorcyclist kept moving backwards, not having the time to use his speed Quirk as he had to dodge each punch. 

"Fine, if we're using brute strength, then this would be a better fit!" he said, pulling out another strange bottle, though this one was green. He gave it a shake, twisted its cap open, and when Ryuga threw a punch, a small green shell thing appeared on his arm, blocking the punch. As Ryuga shook his hand to wave off the pain, the motorcyclist shook another bottle, this one brown, and twisted its cap open. He punched Ryuga square on the chest, sending him backwards. 

"Urgh, what?" Ryuga said, clutching his chest. "How can you use multiple Quirks like that!? Unless... they experimented on you too?"

"Wait, what do you mean?" the motorcyclist said, raising an eyebrow. "Don't tell me... you were being experimented on!? Did you see a bat man, cobra man, or spanner man!?"

"The hell-? No, it was just a bunch of guys in white I saw. But maybe there was someone else there? I did see some weird tacky chair nearby..." 

"Midoriya, did you hear-?"

"Yea, he's got to be!" 

"What are you talking about?" Ryuga said, finally letting his guard down, when three strange creatures came out of nowhere. One looked like a bee, the second looked like a bunch of stalactites (Stalagmites? Which was it...), and the third looked like some weird sort of deer. 

"Smashes!" the two strangers said in unison.

"What the _hell_ are those!?" Ryuga said, pointing to them in surprise.

"You don't know what a Smash is?" the motorcyclist asked.

"I've been in jail for several months with no news! What the hell has been going on out here!?" Ryuga said, when the bee-like Smash flew over and grabbed him, lifting him into the air. "Shiiiiiiit!" he cried, as he got higher and higher. But before he could truly become airborne, someone came leaping to the rescue, grabbing the Smash and pulling it down to the ground. With Ryuga.

"Have no fear, for I am here!"

"Oh man, it's All Might!" Ryuga muttered, realizing how much trouble he's in now. All Might didn't seem to register him though, for some reason, as he turned to the motorcyclist. "I know you've said that I can't help purify these poor Smash victims, but I'm sure I can keep them contain here while you do it!"

"Of course, All Might!" the motorcyclist said, as he looked to the Smashes. "But man, _three_ Smashes at the same time? Misora's not gonna like having to purify so many Fullbottles at once," the motorcyclist muttered, pulling out a strange belt. He slapped it onto his waist, and smiled. "But that means three new Fullbottles! So it's all good! Midoriya, find somewhere safe to hide for the moment!" 

The teen nodded, and went back to the wall he was behind earlier. The motorcyclist pulled out the red bottle from earlier, and a blue one as well. He started shaking the bottles, as weird floating numbers and letters started to appear, which all seemed to be making odd equations that Ryuga did not understand (science was his worst subject in school). He then inserted the bottles into the belt, which, to his surprise, made an announcement.

" **Rabbit! Tank! Best Match!** "

Suddenly, weird plastic model runners came out of the motorcyclist's belt, which formed weird red armor in the front and blue armor in the back. When he finished, the belt asked him a question, " **Are you ready?** "

"Transform!"

The runners slammed onto him, combining the armor, as the belt played a jingle, and announced, " **The Moonsault of Steel! RabbitTank! Yeahhh!** "

"What!?" Ryuga said, not having expected his day to go quite like this. Experimentation, weird monster things, and now a man changing into armor by being slammed in between two halves. "What the hell are you!?"

"Called me Kamen Rider Build," the armored motorcyclist said. "And right now, I've got the winning formula," he added, as he traced his tank-like eye visor thing with the back of his finger, and did a quick hand flick, before summoning a strange weapon from his belt. He pulled the blade, and reinserted it into the handle, turning it into a gun-like contraption. He inserted a white bottle into it, and it announced, " **Ready, go! Vortex Break!** " Build pointed it at the bee Smash that was starting to get up, and froze It kept trying stab Build with its pointy fingers, though he dodged each one. 

"Hm, calling you the Bee Smash would be boring, too straightforward. Same with Wasp Smash," he said, moving back as it swung its hands at him. "And I already used 'Needle Smash' for the last one... I know! Stinger Smash! Still related to bees and wasps, and different enough from needles! Perfect!" 

As he said this, the other Smashes, the spiky one and the deer one, ran towards him, throwing their own punches at him. He dodged them, letting them punch the Stinger Smash instead. "Hm... I guess I'll call you the Rock Smash 'cuz of your rockier appearance," he added, looking at the spiky Smash, before turning to the deer one. "... And I'll call you the Antler Smash!" 

The three Smashes regained whatever composure they had, and went after him. He summoned his weird weapon again, and struck the Antler Smash right on the head with it. The Rock Smash swung to the side and threw a punch, which Build blocked, but that left him opened to the Stinger Smash thrusting its stinger fingers towards him, which caused a small explosion that knocked him backwards. 

"Ow! Geez, this is a little more of a challenge than the last few Smash attacks," Build said, dusting off the attack, watching as the Stinger Smash decided to pull out of this fight to capture Ryuga, and the Antler Smash decided to face off against All Might, who dodged each attack it made. He pulled out the bottles in his belt, and got out another red bottle with a bird on it and a gray one with a robot on it. "Let's see how you handle a burning metal heart!" 

"What?" Ryuga said, confused as he dodged each grab the Stinger Smash made for him.

"It means, let's bust out a new combination!" Build said, inserting the bottles into his belt. 

" **Phoenix! Robot! Best Match!** "

"Yes! I knew I was onto something with the Best Match being an avian Fullbottle paired with a gray one! Let's go!" Build said, cranking his belt's handle. New equations appears around him, smacking into the Smashes distracting them, as a red runner formed in front of Build, and a gray runner formed behind him, with a third small runner with a red feather-like cape forming behind the gray runner.

" **Are you ready!?** "

"Build up!" Build said, as the runners slammed together onto him again, forming his new armor. The red parts of his armor were now a different shade than before, with a flame-like right shoulder armor and a flame-like blade on his right forearm, and his helmet's left eye was now shaped like a fiery bird. The blue, on the other hand, was now replaced with a dark gray, and instead of a left hand, he had a giant mechanical pinching claw, while his left shoulder armor had a odd tiny piston-like contraption on it, and his right eye resembled a folded-up robotic arm. His chest armor had a large flame-like decoration on the upper left side, while an exposed engine-like pattern laid underneath it. On his back was the red feather-like cape. 

" **The Immortal Weapon! PhoenixRobo! Yeahhh!** "

"Now I've really got the winning formula!" Build said, repeating the same hand gesture from earlier. The Rock Smash charged at him, and swung its right fist towards Build, who caught it with his robotic hand. He began to twist the Rock Smash's arm the other way, causing it to growl in pain, before creating a small fireball in his fist and punching the Rock Smash in the face, sending it backwards. When it saw its companion falling to the ground, the Antler Smash returned its attention to Build, lowering its head and pointing its antlers towards him and charged. Build calmly stared at it, and leaped into the air, suddenly flying as the Antler Smash rammed into a nearby wall of pipes, getting its antlers stuck between the spaces. 

The Stinger Smash turned to look up at the flying Build, shaking off the melting ice that was stuck on its wings, and flew up to challenge Build. Ryuga took a deep breath and sighed, finally having the opportunity to rest, as the Rock Smash was in too much pain to really do anything, and the Antler Smash was still trying to pull itself free. All Might did the same, seemingly tired from having leaped from where he was to here.

The Stinger Smash pointed its bulbous bee butt at Build, and started launching energy stingers at him. He created a wall of fire that absorbed the stingers, and pushed it towards the Smash, igniting it. As the fire dissipated as it crash-landed onto the ground, Build landed, and started to crank his belt's handle again.

"And now for the finish!" Build announced, as the belt announced alongside him. " **Ready, go! Vortex Finish!** "

A large energy projection of his robot hand formed around it, and he launched it at the Stinger Smash, watching it fly around and grabbing the Rock Smash, which recovered from its pain, and the Antler Smash, which had finally freed itself from the pipe wall. The three Smashes struggled to get out of the energy robotic hand, but to no avail, as Build created a powerful fireball in his right hand, and threw it at them, turning into a phoenix before it collided with them, causing them to explode. They fell to the ground, struggling to get up, but they were too weakened to do anything. Build pulled out three clear bottles, and pointed them at the fallen Smash, light particles flowing into them, before three teens were all that were left of the Smashes.

"Ooooh, my aching head," the former Rock Smash, a boy, said, rubbing his head. "What happened?"

"I feel like I just woke from the hardest dance party of my life," the former Stinger Smash, a pink girl with horns and black sclera, said, holding her aching legs and arms. 

"I wanna just go home and _pass out_ ," the former Antler Smash, a girl with still large horns and hoof-like feet, said, sprawling out on her back and closing her eyes. "I should've listened to my friends back home about how _crazy_ Touto was."

"That was so easy!" Build said, so cheerfully that you could just imagine the smile he had underneath the helmet. "PhoenixRobo is leagues above RabbitTank or LionCleaner! I think I'll make this my defAAAAAAAAULT!" 

As Build finished his sentence, his Robot half started to short-circuit, as All Might, Midoriya, and Ryuga watched as his limbs and head started to spark. Even the three former Smashes looked on the spectacle.

"Hot, hot, hot! Gotta Build up quick!" he cried, pulling the bottles out of his belt and quickly inserting the bottles from earlier into his belt, cranking as fast as he could to engage the form change as fast as he could. Once he was back to his red and blue form, he sighed. "So the drawback of that Best Match is that Phoenix, while boosted by Robot, causes Robot to overheat and short-circuit. Not a form to use for long periods of time. Man, can't believe that Best Matches would have drawbacks, either..."

"So, now that that's settled," All Might said, turning to face Ryuga, who instantly got into a fighting stance. "You're going back to the proper authorities and serving your sentence, Ryuga Banjo."

"Like hell I am! I already told everyone, I never rigged any fights! And I certainly didn't kill that Katsuragi guy!" Ryuga said, still insistent on his innocent. He was a lot of things, but murderer was not one of them. Ever. 

"Don't lie to me! If you had gone to prison, that means that you failed my friend Tsukauchi's lie detector Qu-"

"Who the hell's Tsukauchi!? There wasn't anyone with that name when I was interrogated!"

"What?" All Might said, raising an eyebrow. "But I was told-"

"Whatever _you_ were told, it didn't happen! I didn't go through some lie detector Quirk test! I didn't even have the chance to say how I was innocent! I was just thrown in jail!" Ryuga said, as tears started to stream in his eyes, his fists dropping to his side. "I-I'm a lot of things. An idiot, a fool, too trusting, too emotional, a musclehead, anything like that. But I'm not a murderer. I never killed anyone!"

"Not to mention he's our best lead now," Build said, looking at All Might. All Might looked at him, before looking at the teen who confirmed it. "He said he escaped being experimented on by the same guys in white."

"And unlike other people, he did completely conscious, enough that he could make it all the way here," Build said, turning to him. "So, can you lead us to them, so we can stop them?"

"Are you kidding!? I don't remember where I was!" Ryuga snapped. "I ran as fast as I could without looking back! Like I'd want get caught again!"

Just then, a car screeched to a stop nearby, followed by police officers and Guardians. The car door opened, and the current head of the Institute (Gentoku Himuro, if Ryuga remembered correctly) got out, followed by his aide. He looked at everyone, and stopped onto Ryuga.

"Congratulations on capturing the convict, All Might," Gentoku said, stroking his beard. "And the Kamen Rider, as well. We'll take care of things from here, no worries. How dare you bring children into this, you felons."

"No..." Ryuga said, softly. "I can't go back. I didn't kill anyone. I didn't do anything wrong!" 

"Sounds like what a criminal would say," Gentoku said, dismissively. "Come now, don't make this harder."

Build started to rub the back of his head, trying to think of what he could do when his eyes rested on his motorcycle. He made a whistling gesture to it (in spite of wearing a helmet), and it came towards them, pushing everyone out of the way. "Come on, get on!" he said, motioning Ryuga to get onto the bike. Without a second thought, Ryuga hopped on, and the two started to drive away. 

"Don't worry, I'll catch them!" All Might said, laughing. Though Midoriya could see through the laugh, knowing what he was truly planning. "Young man, please take care of your peers while I go after them!" 

All Might started to run after the two, who had gotten a good headstart. Police officers and Guardians started firing after Build and Ryuga, with a Guardian squadron already moving out, but Gentoku yelled at them, "What the hell are you doing!? Stop shooting at All Might, he's the Symbol of Touto! I will not have you all injure him while he's attempting to capture villains! Utusmi! Send the order to the Guardians to stop!" 

"Already on it, sir, but the ones that are already pursuing them will take a while to stop," Utsumi said, as he tapped on his tablet. "Hopefully All Might will just break them, since they're replaceable." 

"Hope you know what you're doing, Mr. Kiryu, All Might," Midoriya thought, as he ushered the three drowsy Smash victims away, staying low so that no one would notice them leaving. 

* * *

"I have _no_ idea what I'm doing," Build said, as he drove away from the crowd of officers and Guardians. "What am I thinking!? Build's super unpopular, I just tanked any possible good will down the drain by helping you out!" 

"Geez, thanks for that, rabbit head," Ryuga said, rolling his eyes. "Just keep your eyes on the road so we don't die! All Might's gonna-"

"Be here!" 

"AAAAAAAAAAH!" 

"Calm down, he's on our side," Build muttered, when Guardians started to catch up towards them and fired at them. Build swerved the motorcycle out of the way, while All Might jumped into the air, landing on a few.

"I certainly hope they don't mind me breaking a few of these, since they did technically attack me!" All Might said, when the Guardians changed direction.

"Immediate threat detected; commencing arrest," a few of them said in a robotic voice, moving away from Build and Ryuga. 

"Uh oh," Build said, looking back. 

"Curses! I'll get you hooligans some day!" All Might said, with a flair of drama as he started to fight the Guardians. 

"You liar! He was totally gonna capture us!"

"Seriously? He's just acting to cover up that he's on our side. Guardians have cameras, you know," Build said, as Ryuga watched the group of Guardians getting tossed around and broken apart by All Might, who quickly and subtly threw up a thumbs up sign at them. "Can't have the Number One Hero fraternizing with vigilantes in public after all. Especially a vigilante who's helping an escaped murder convict."

"I didn't kill anyone!" 

"I know, I know. I can tell by your eyes. And besides, a real idiot wouldn't acknowledge their lack of knowledge, either," Build said, taking off his belt and changing back to his regular identity. "Plus, you're my and Midoriya's best bet to finding out who this organization is, and why they keep doing this."

Ryuga looked away for a bit. He got why they'd want his help, and he wanted to, but honestly, he wanted, no, needed to be clear his name of everything first. He doesn't want to keep living like this, as a criminal, when he was innocent. Then he can go back to his life with Kasumi, back to his life of boxing, back to helping people, without any of this heavy weight on him. "Fine, but like I said, I don't remember where I got out of and how to get back there."

"It's alright, we'll just jog your memory," Build said, smiling. "Well, I think first off, we need to properly introduce each other. My name's Sento Kiryu."

"... Ryuga Banjo."

"Well, Banjo, I think I should tell you that right now, your fly's down," Build said, his smile turning into a smirk. Ryuga looked down, and indeed, his pant's zipper was down.

"Wha!? For how long!?" Ryuga said, reaching down to zip it back up. 

"Since the beginning of our scuffle."

"You little-!"

"Heyheyhey, stop that! I'm driving!" 

* * *

Meta Bolt sat at the edge on top of the Skywall, watching as Sento and Ryuga drove down the empty road. "Hm, a wannabe hero and a murder convict. Can't say that's a combination I'd see."

"Bolt," a voice said, coming from behind him. "What is the meaning of this?"

"Oh, Rogue, fancy seeing you here," Bolt said, not bothering to turn around. "It's pretty rare that you of all people are up and out."

"I told you to take care of capturing Ryuga Banjo."

"And I did."

"By creating _three_ Smashes? I told you that you're not to rely on using the Steam Rifle for Smashification!" 

"Pipe down, it was an emergency. I thought you hated losing test subjects like Banjo and Midoriya. Admittedly, Stalk was the one who let Midoriya go, so it's not like I know the reason."

"And I'd like it to keep it to myself, too," a third voice said, joining them. "Yo, Bolt, Rogue."

"Tch," Rogue said, the scowl behind his helmet palpable. "Why is it that you two keep messing around with my orders? We need subjects like them to-"

"Yea, yea, 'prepare for war', we know," Bolt said, getting up. "Thing is, you're not the only one in charge of Faust. This was a collaboration between all of us, along with the backing of some powerful sponsors. So quit thinking we're just your followers, and let us handle things the way we think we should." 

"Eh, you guys are too serious," Stalk said, as he stretched his arms and shoulders. "We have all the time we need to prepare, and what's two or three 'escaped' experiments? Besides, they can still be useful freed. All we need really is to find that missing data." 

"Indeed," Rogue said, crossing his arms. "And knowing him, he hid it somewhere secured and with only one clue about how to access it."

"Don't worry, we'll find it soon enough. The Kamen Rider will probably be the key," Bolt said, getting up and past Rogue, patting him on the shoulder. "Trust me, when the war breaks out, Faust will come out on top."

As Bolt and Stalk left Rogue to ruminate on what has been happening, Rogue stood there, deep in thought. While his concerns about Bolt and Stalk never faded as the two constantly pushed and pulled orders he gave them, he did recognize that they were brilliant in many regards, and that the progresses his cohorts made were undeniable and valuable to their overall goal. 

Any reservations he had, it had to be pushed aside. After all, they had a war to prepare for, and he'll be damned if Hokuto and Seito had the advantage over Touto. 

**Notes for the Chapter:**

> \- Yes that's right, I'm gonna do my own Build-esque introductions for chapters now. All notes I have will now be relegated to the end notes instead so that I can make use of the beginning notes for the chapter. I tried using the chapter summary, but I was running out of characters too quickly on that.  
> \- I gave a hint to it in the last chapter, but I'm officially enlarging the secret lair a bit more. In place of the single bed, there's now a hallway with more rooms for all of the characters to sleep in. And I'm giving it the name "Build Shop" 'cuz it's catchier that way.  
> \- Time for MORE RUSHING. You guys think I wouldn't introduce Sawa, Gentoku, Utsumi, and Ryuga any time soon? Well, they're here now. Sorry if it seems like I'm skipping a lot of time on this, but again, I want to get to the more interesting parts, and I don't want to be too slow with this.  
> \- I'm sorry if it doesn't seem like All Might and Izuku have done anything truly substantial so far. I tried fixing that by having the fight scene with Meta Bolt, but I understand if it's a little too short for people's liking. And if it had Meta Bolt at the advantage, gotta keep the villains reasonably threatening, especially since Meta Bolt and Faust are a little more present than the League of Villains. I do have big plans for Izuku, and I didn't mention him liking the Beetle Fullbottle and the conversation about Sento making more Build Drivers for nothing now. Plus with his Hazard Level giving him a much needed boost to handle One for All, he's gonna get stronger a little faster than he did in the canon.  
> \- Why is All Might a lot more willing to work with a vigilante than he might be in canon? Well, I figured that with the Skywall Incident, that he became a lot more aware of his limitations and how others can save people in different ways. Plus, I'd think he'd be willing to trust Sento a lot more after seeing how he reacts to Meta Bolt's callous behavior about science and people. So while he can't let himself be seen in public working with the Kamen Rider, I'm sure he's more than willing to let him operate without issue. Not to mention that I already established that he was already slightly wary of his position as the "Number One Hero" and "Symbol of Peace" thanks to the Skywall Incident in the first chapter, so I think he'd be a little more loose with his opinions.  
> \- One of the reasons why I gave PhoenixRobo, a form that, by all means, was the strongest of the regular Best Matches, a weakness like that is precisely because that it was the strongest of them, and the way I set the story up with Bakugo's Smash essence giving Build the Phoenix Fullbottle and Mei's Smash essence (as if it's not obvious who she was, or who any of the Smash victims that are currently "unnamed", really) giving Build the Robot Fullbottle meant giving him full access to PhoenixRobo waaaay earlier than when it appeared in series. So I had to give a suitable weakness to PhoenixRobo, and what better way to do that than making the Robot half literally overheat due to the Phoenix half? I think it makes sense to me. Expect some more unique weaknesses added to Best Matches when or if they appear, especially if they're ones that were never utilized in show.  
> \- Sorry if the ending isn't the same as the canon first episode of Kamen Rider Build for you Build fans, since that was a legitimately cool ending. I personally think that with the interference of Quirks and heroism as a legitimate occupation that it would end pretty differently in comparison. Not to mention that the events leading up to it were already different, and Build outright BEGINS as a "fugitive" due to being labeled as a vigilante.  
> \- If you think Ryuga fought a lot better against Sento in their first "fight" than in canon, you'd be right. I figured that with giving Ryuga the background of going through a hero course and becoming at least a sidekick while also being a boxer, that he'd have a much better fighting style and more experience in villain fights than he did in canon. Consequently, his hero background's definitely gonna affect his character arc a bit, but it's still gonna be similar enough.  
> \- EDIT (3/24/2020): I changed the timeskip to be 8 months instead of 5. I was having a hard time figuring out how to pad out the other half before the entrance exams, until I got tired of it and decided to increase the number of months instead, and added one more Fullbottle to compensate (I don't want too many Fullbottles to be made, I got plans for a number of them). Consequentially, I'm going to be going through other chapters to make sure there wouldn't be any contradictions, as well as adding Giraffe to the first Build Files.  
> 


	4. Build Files One

**From Sento Kiryu's PC**

**The Build Files: Best Matches**

**RabbitTank** ( _The Moonsault of Steel_ )

 **-** The first Best Match; was already existing by the time I had taken up the responsibility as Build. 

\- The agility and speed of Rabbit helps balances Tank's strength and durability. The result? A Best Match that, while not the fastest and strongest, still gives a considerable boost in abilities, especially compared to Trial Matches. 

\- Unlike the other Halfbodies created by the Fullbottles, RabbitTank's armaments are equipped on the legs. Rabbit provides the Rabbit Foot Shoe, which increases the jumping height of any Match, and Tank provides the Tank Roller Shoe, which can move to increase kicking strength or as an actual tank tread (WARNING: You will be forced to balance on one leg while using this ability due to the Rabbit Foot Shoe not having a similar tank tread, and it can only be used as such on flat horizontal surfaces safely).

\- NEW NOTE: The Rabbit and Tank Fullbottles have an oddly high synergy rate compared to the other Best Matches that I've discovered, giving it solid stability and little to no weaknesses in comparison to LionCleaner's Long Range Cleaner potentially clogging up and the Gold Lio Gauntlet's charge-up attack or PhoenixRobo's overheating issue. Because of this, RabbitTank's capabilities will be used as a baseline to compare future Best Matches to. 

\- NEW NEW NOTE: RabbitTank's Vortex Finish is the Tank-Down; a white energy sloping graph that pins the Smash in between it, and by stomping a hole into the ground and creating a pillar, I can get onto the graph and slide down it, delivering a powerful kick with the Tank Roller Shoe. 

**LionCleaner** ( _The Mane Cyclone_ )

\- The second Best Match; while I've had the Lion and Vacuum Fullbottles for a couple months now, it never occurred to me to try Matching these two. Admittedly, it's mostly due to using the Lion Fullbottle as the power source for the Machine Builder. 

\- Is relatively slower than RabbitTank, but not by much; basically the inverse of RabbitTank, in that its the Lion Halfbody that provides the power and strength, and Vacuum that provides the speed and agility. What this Best Match does bring is special armaments that enhance attack abilities rather than stats.

\- The armaments of this Best Match are the Long Range Cleaner and the Gold Lio Gauntlet. The Long Range Cleaner provides the ability to suck up energy attacks and explosions and convert it into energy that the Gold Lio Gauntlet can use to attack with without the need for the charge up time. It can also such up solid projections and fire them back, or use the energy it converted to use as energy blasts as well. The Gold Lio Gauntlet grants the ability to convert the bioenergies created by the user's (in this case, mine) body to create lion-shaped energy blasts. It takes time to charge, and the longer the charge, the stronger the blast, but as stated before the Long Range Cleaner can shorten this charge time by sucking up energy attacks and explosions to convert into usable energy. When used in a Trial Match, the Gold Lio Gauntlet's blasts are incredibly short-ranged, and are essentially beefed-up punches. 

\- As revealed in the fight against Meta Bolt, LionCleaner's biggest weakness is that the Long Range Cleaner _can_ be clogged, and it takes a Vortex Finish to unclog it if its substantial. Not to mention that prolonged usage of the Gold Lio Gauntlet's energy blasts will drain me if I'm not careful due to its reliance on my bioenergy. 

\- NEW NOTE: LionCleaner's main Vortex Finish is the Cleansing Bite; using the Long Range Cleaner, I pull in Smash with its powerful air suction to keep them from escaping (might be useful for use against flight-capable Smashes) using the Vortex Finish's energy boost to charge the Gold Lio Gauntlet to fire a giant energy blast. 

**PhoenixRobo** ( _The Immortal Weapon_ )

\- The third Best Match; I was onto something when I tried pairing the Phoenix Fullbottle with a gray one.

\- It's the superior to RabbitTank in every way; it's faster, stronger, more agile, and instead of jumping height, it has the ability to fly. Would be perfect if it weren't for its weaknesses. 

\- The armaments of this Best Match are the the Phoenix Halfbody's Flame Reviver gauntlet and the Imperial Wings cape, and the Robot Halfbody's Demolition One hand and BLD Arsenal Shoulder. With the Flame Reviver, PhoenixRobo is capable of generating powerful fireballs, which are amplified by the Best Match's power boost, and the Imperial Wings cape allows the Best Match to fly into the air and wreath itself with flames. The Demolition One hand allows PhoenixRobo to dismantle and crush targets, while the BLD Arsenal Shoulder allows any mechanical object dismantled to be refitted to create a robot army (so far testing this ability has allowed me to create up to five Guardian-like robots before the Best Match overheated) which lasts as long as the Best Match is in use. 

\- Despite its overwhelming power and ability increases, PhoenixRobo, despite being a Best Match, has one extreme flaw: Thanks to the Phoenix Halfbody, the Robot Halfbody is prone to extreme overheating and short-circuiting if used for too long. This seems to be the case for most of the Trial Matches when the other Fullbottle is mechanically-based such as PhoenixTank and PhoenixJet, while a Trial Match like PhoenixPyramid seems to be able the Phoenix Halfbody's fire well enough. But in PhoenixRobo's case, not only does it come with this overheating issue, but it's amplified by the nature of the Best Match's power boost, causing PhoenixRobo to overheat faster and much more drastically. 

\- NEW NOTE: PhoenixRobo's main Vortex Finish is the Burning Birdbot; I create a energy projection of the Demolition One that I launch to catch as many Smashes as possible, while generating a large fireball in my right hand with the Flame Reviver, before firing it at the Smashes and weakening them enough to extract the Smash essence. The reason for the name is mainly due to the fireball changing into a phoenix-shape, and the usage of a projection copy of the Demolition One to pin down Smashes. 

* * *

** From Izuku Midoriya's "Secret Rider Files" **

** Abilities Granted by Fullbottles W/O A Build Driver **

**Rabbit Fullbottle** : Grants user bursts in super speed; lasts about 5 seconds, not ideal for long-term travel 

**Tank Fullbottle** : Grants user powerful explosive punches; use is similar to Kacchan's Explosion Quirk, and the drawback is similar

 **Phoenix Fullbottle** : Grants user limited pyrokinesis; does _not_ grant fire resistance, at least not enough for prolonged use; recommended only for emergency situations

 **Turtle Fullbottle** : Grants user an impenetrable barrier; only lasts as long as user holds still, and cannot be shared or moved to others without disrupting the barrier and forcing the user to shake and twist the cap again

 **Gatling Fullbottle** : Turns user's free hand into a gatling gun; very similar to some Transformation-type Quirks that way; not a very comfortable feeling if unused to transforming parts of body; might have to get used to through repeated usage

 **Lion Fullbottle** : Grants user the ability to use bioenergy for small shockwave punches; drains user stamina if overused within a short time span

 **Pirate Fullbottle** : Grants user limited aerokinesis and hydrokinesis; while neither ability is particularly too powerful, the fact that the Pirate Fullbottle grants two weak abilities to generate and control two elements gives it an advantage over other Fullbottles

 **Beetle Fullbottle** : Grants user "drill punches" by way of generating an "aura" that spins like a drill; out of all the Fullbottles, I find this one to be the most useful for me, especially considering my general physical enhancement Quirk (Odd that it's Beetle that grants a drill ability, and not like, a Drill Fullbottle. Does that mean that there isn't one? What Fullbottles _can_ be made?)

 **Jet Fullbottle** : Grants user a jet-shaped "jetpack" projection that allows for flight; not a bad form of transportation, but not necessarily the most subtle 

**Vacuum Fullbottle** : Grants user a "vacuum" mouth ability that sucks in attacks and converts them into energy mouth blasts; downside is that you taste what you absorb and fire back, and nothing tastes pleasant that way 

**Refrigerator Fullbottle** : Generates an energy projection of a refrigerator that works; lasts pretty long; the one I created trying it out lasted a month before finally disappearing; good for outdoor survival if you have it and you need to keep any food you hunt for meat or gathering wild fruit or vegetables cold (might be a good combination with the Phoenix Fullbottle to cook food with)

 **Robot Fullbottle** : Allows user to come up with robotic schematics within seconds with the materials around; does not give the ability to build them quickly, though (only can be done when used in the Build Driver)

 **Gorilla Fullbottle** : Grants user temporary super strength; rather useful, but redundant with my general physical enhancement Quirk

 **Pyramid Fullbottle** : Generates an energy pyramid that can trap people inside; the one that Sento got stuck under when we experimented with it lasted until the morning (Had to apologize for nearly making him late for work)

 **Remote Control Fullbottle** : Allows user to access the controls to one particular electronic that they focus on; cannot be used on multiple electronics at once 

**Dog Fullbottle** : Enhances the user's senses greatly, akin to a dog's; WARNING! If unprepared, sensory overload will occur, and you will be outcold for two hours (had to make up training time with All Might for that) 

**TV Fullbottle** : Allows the user to see a holographic "TV" screen that, used in conjunction with shaking the Smartphone Fullbottle, allows for face-to-face communication; otherwise without it, the TV Fullbottle can only access public TV (apparently this combination can't be used with the Build Driver itself, I wonder why)

 **Smartphone Fullbottle** : Creates a holographic smartphone that can function as a real one; might be useful in emergency situations; when used with the TV Fullbottle it can allow for face-to-face communication 

**Giraffe Fullbottle** : Increases the length of user's neck; not recommended for use in encased areas

 **Hedgehog Fullbottle** : Allows user to generation temporary quills on arms for attacks and protection; like the Gatling Fullbottle, functions similarly to Transformation-type Quirks, and might need repeated usage to get used to it

* * *

**From Sento Kiryu's PC**

**The Smash Files**

**Fang Smash**

\- Extracted essence created the Lion Fullbottle

\- The first Smash I fought; being only armed with the Rabbit, Tank, Jet, Pirate, and Gatling Fullbottles, I didn't have much to fight with other than sheer force and getting used to the Build Driver

\- Its giant fanged mouth was capable of firing powerful blasts with each roar, and its blade-like claws gave it powerful close ranged attacks. Its tail was also trouble, considering it could fire lasers

\- To defeat the Fang Smash, I had to rely on a Gatling-powered Vortex Break with the Drill Crusher to cripple it (its leg armor was thin and easily penetrable), and then using a Vortex Finish with RabbitTank

\- The victim was a man wearing a lion's mane; seemed like he was in his early thirties 

**Shell Smash**

\- Extracted essence created the Turtle Fullbottle

\- The second Smash; while the situation was basically the same as before, having Lion helped expand the repertoire of abilities I could use

\- Its thick shell-like armor kept me from defending it quickly, as most of my attacks couldn't get through it. Not to mention that it could create barriers to push me away from getting too close

\- Managed to defeat the Shell Smash by using LionJet to fly into the air and drop the Shell Smash onto the ground, softening its armor just enough for a RabbitTank Vortex Finish. 

\- The victim was some sort of old man with a turtle shell strapped to his back; couldn't really tell his age, but while unconscious he seemed to keep talking about younger girls... not someone I'd necessarily associate with personally (though I guess with how old he physically appeared, he didn't have a lot of options for dating) 

**Spiral Smash**

\- Extracted essence created the Beetle Fullbottle 

\- The third Smash; having the Turtle Fullbottle really helped out in this fight, as its shield-generation capabilities allowed me to take the drill punches without a problem 

\- While it having basically four arms with four claw-like fingers on each of them that could spin, a huge horn that also spun, giant scissor-like mandibles, and wings, making it certainly a tough foe to fight, Turtle's presence really helped negate a lot of the attacks

\- By using Trial Matches with Turtle, I was able to defend myself from all the drill and mandible attacks. I used TurtleGatling to fire at the Spiral Smash from a distance and TurtleJet to fly while trying to offset the heaviness of the Turtle half. Using Vortex Attacks helped weaken the Spiral Smash, but in the end, it had to be defeated by a RabbitTank Vortex Finish (seriously, I really need more Best Matches, using RabbitTank gets a little wary when it's the only one I have)

\- The victim, strangely enough, didn't really have any beetle-like features, only had orange skin; seemed to be in his mid-twenties

\- NEW NOTE: I have given Midoriya the Beetle Fullbottle after the Claw Smash, so I no longer use it too much myself

**Ice Smash**

\- Extracted essence created the Refrigerator Fullbottle

\- The fourth Smash; it was tough to beat this one, if only because none of the Fullbottles I have didn't really give me an edge (none of them provided any sort of pyrokinesis), so I had to improvise 

\- It was strangely jellyfish-like in appearance, with tentacles all over the body, but it didn't make use of them in the beginning, making it seem like they were more decorative for the most part until it started to point them at me when I got close and sprayed water that instantly froze on my armor; not to mention its hand could produce a lot of ice balls and icicles blades

\- As stated before, since I don't have any Fullbottles that provide pyrokinesis, defeating the Ice Smash was a challenge. It also had a decent amount of range to pick from with it being able to freeze me up close with its tentacles, throwing large balls of ice, and using icicle blades. I was forced into a long range battle using Gatling Trial Matches until I managed to find out that BeetleGatling did some solid damage by using the gatling gun generation ability on the Gatling Halfbody and firing drilling bullets. While I did damage it with a Vortex Attack, I had to finish everything off with the RabbitTank Vortex Finish

\- Victim was some sort refrigerator man(?) who kept yelling "Freezer freezer freezer" over and over, even unconscious (Related to that hero Wash perhaps? Probably was just wearing a costume then if that's the case)

**Sucking Smash**

\- Extracted essence created the Vacuum Fullbottle

\- The fifth Smash; it was _ridiculously_ hard to beat this one, since nothing, sort of punches, kicks, and strikes with the Drill Crusher could beat it, since the Smash would just suck up all the attacks, using them to either power itself up or fire them back at me

\- The large mouth it had sucked in all the bullets and energy attacks I had. Trying to block it up with things didn't work either, since its hands were also capable of sucking in attacks. And it could fire back any attacks it made, or used it to power itself up to give itself more strength and speed. In the end, just had to use BeetleTank and LionTank to browbeat the Smash into submission until it was weak enough for a RabbitTank Vortex Finish

\- Victim was a girl with a pretty wide mouth; seemed to have had a Quirk related to eating, explaining her Smash-ified Quirk 

**Explode Smash**

\- Extracted essence created the Phoenix Fullbottle

\- The sixth Smash; defeating this one was a little quicker than the previous ones, probably 'cuz I've gotten a lot better and a lot faster with coming up with what to beat Smashes with; that, and I did have the Refrigerator Fullbottle, which helped me keep this guy in place and blocking all possible ways for him to use his Smash-ified Quirk (could've used that Phoenix Fullbottle on that Ice Smash, though, ironically) 

\- Unlike the other Smashes I've handled, this one acted a lot more erratically, just using its explosive powers without a care; that made it pretty tough in a way, since it had a lot of choices on how to use the guy's explosive Quirk; his fingertips had blowtorch-like openings that allowed him to fire off small explosions while his palms had larger ones for bigger explosions, his chest had openings that could fire missiles that could explode, and he had a jetpack-like thing on his back, that I'm very sure would've been used to make giant explosions (thank goodness I managed to extract the essence before that could happen) 

\- A big challenge about this was the fact that, unlike the previous Smashes I faced, there was a giant crowd that had gathered there before thanks to this victim being caught up in a regular villain attack just minutes ago. This meant that whoever's been turning people into Smash figured out a way to do it from a distance now instead of whatever process they used before. Admittedly, I managed to get there in time (thanks to literally passing by through the alleyways on the Machine Builder), so the damage was minimal (not counting what was there earlier)

\- To defeat this Smash, I started off with RabbitTank (again) and used the Drill Crusher to soften him up a bit, though that didn't last too long when he started firing the missiles. I tried out TurtleTank for the first time, and while it did give me some solid protection and a few good punches, being super slow and having a big turtle shell-shaped shield on my right shoulder was not too fun, so to regain some much-needed agility, went back to RabbitTank, and used a Refrigerator-powered Vortex Break to freeze the Smash (which, in retrospect, is something I should've led with), and then ended it all with a RabbitTank Vortex Finish 

\- Victim was Katsuki Bakugo (aka "Explodey Boy"), a middle school student who's a U.A. hopeful and ended up being the victim of two consecutive villain attacks thanks to this (kid's probably not gonna have a fun day at school after this, since he didn't seem to be that much of a pleasant guy to begin with) (the news media seems to be eating this kid up, though, and so are some pro heroes, so I guess not every pro hero's gonna be that great of a person to begin with) 

**Strong Smash**

\- Extracted essence created the Gorilla Fullbottle

\- The seventh Smash; defeating this one was also a bit more challenging, considering it had some real strong punches, and was really tough, with a lot of my beginning attacks not doing much to it until I started using PhoenixGatling to soften it up

\- Unlike the previous Smashes I've fought, this guy didn't really have anything too flashy about him, just straight-up enhanced strength and endurance (seemed like it gave Midoriya a pretty good run for his life, since he left a lot of holes in a bunch of garbage piles); didn't make it any less tough to fight

\- Like all fights, led in with RabbitTank and the Drill Crusher, but neither of those deal much damage, and I actually got punched a couple times by the Smash (thank goodness the armor the Build Driver creates helps absorb a lot of the damage), so I went with PhoenixGatling (while it's not a Best Match, I had a pretty good feeling that I'm onto something with an avian Fullbottle and a gray Fullbottle Best Match) to soften him up, but using both the fire generation of Phoenix and the gatling gun generation of Gatling took a lot of energy out of me, so of course, finished it all off with a RabbitTank Vortex Finish

\- Victim was a _giant_ guy with six arms, white hair, and a mask; was more of an octopus/squid person than a gorilla (he was also pretty ripped and _heavy_ , so he's probably as strong as a gorilla);

\- Honestly the biggest takeaway from this fight was the fact that I met All Might and his protege Izuku Midoriya, who's one of my best leads to the mystery of the organization behind all this and my own memory loss, since he was also experimented by them (But he isn't one of the Smash victims I saved, so is he just like me? He can possibly become a Build Driver user in the future if that's the case). Either way, having a pro hero like All Might working with me lifts a lot of doubt about what I'm doing (which is surprising that All Might's chill with working with a vigilante like me; in another world, he might not have even considered doing that), and Midoriya might prove to be a good lab assistant 

**Claw Smash**

\- Extracted essence created the Robot Fullbottle

\- The eighth Smash; while it was challenging to fight at first thanks to its homing bullets and launching claws, using LionCleaner (super glad to get a new Best Match _finally_ ) helped give me the edge

\- Out of all the Smashes, this one was probably the most robotic-like unlike the past ones (which is fitting, considering that the Robot Fullbottle got created from this); it had telescoping eyes, launching claws (like the type you'd see in crane games), and its shoulders had guns that could fire homing bullets

\- While it was challenging at first, especially having to make sure it didn't go after All Might or Midoriya, once I had LionCleaner, it was all over thanks to using the Long Range Cleaner to suck up the bullets before they had a chance to home in and firing them back, and using the Gold Lio Gauntlet to attack with

\- Victim was a pink-haired girl with dreadlocks and yellow eyes with crosshair-shaped pupils; seemed to be about as old as Midoriya 

\- Once again, the biggest takeaway from this fight was the fact we got a lead on the organization; we know that the spanner man is named Meta Bolt, and if his skills are what they are, his allies (the bat man and the cobra man) are probably just as strong and experienced as he is, especially if he had the advantage over Build; I swear, we'll find out the truth about him and his organization, and stop their Smash experiments

**Triangle Smash**

\- Extracted essence created the Pyramid Fullbottle

\- The ninth Smash; despite its deceptively simple name, the Triangle Smash was a pretty tough foe to fight all things considered, since it was a lot of lasers, much more than you'd think with a Smash that produced the Pyramid Fullbottle

\- The Triangle Smash was able to create energy projections, all of which were triangular or pyramid-shaped. It was capable of making multiple projections at once, using them to shield itself from attacks, and could create ones that acted like drones to fire lasers; all in all, it focused a lot on protecting itself while firing from a distance

\- All Might was instrumental in figuring out how this Smash fought; he had leaped behind it and gave it a light punch (well, light for him I presume) while I was drawing its attention with TurtleGatling; as it turned out, this Smash couldn't generate projection behind itself; luckily it turned around to face All Might, and I was able to use TurtleGatling's Vortex Attack to weaken it from behind, before finishing the extraction with LionCleaner's Vortex Finish

\- Victim was a guy with a giant triangular nose and chin; very spindly, very lean

**Button Smash**

\- Extracted essence created the Remote Control Fullbottle

\- The tenth Smash; fighting it straightforward wasn't hard, but it was having to figure out that using a machine-based Fullbottle like Tank or Jet wasn't going to cut it, and was forced to use ones like Pyramid to have a chance

\- The Button Smash wasn't remarkably strong by any means, but its ability to "hack" into the Tank, Jet, Gatling, and even Vacuum and Refrigerator Halfbodies due to their mechanical nature (didn't even think that those last two would be even affected) and make them nonfunctional was what provided the challenge, not to mention its ability to control nearby machinery as well (really wished it hadn't appeared in one of those abandoned factories that got shut down after the Skywall Incident happened)

\- Luckily I had gotten the Pyramid Fullbottle a few days prior to this fight, so I was able to at least have a fighting chance thanks to it. Unfortunately I was unable to find its Best Match in the fight, so I had to resort to using the Vortex Attacks of TurtlePyramid (being able to use two forms of barriers, one of which could be used offensively as well was an interesting but very, very cumbersome and slow Trial Match), PhoenixPyramid (turning the Pyramid's lasers into fireballs), and BeetlePyramid (which gave the Pyramid's lasers a spinning effect) to weaken it until it couldn't use its controlling powers to take it down with a RabbitTank Vortex Finish

\- Victim was a plain guy with messy hair like Midoriya, but it was purple instead; seemed pretty tired, too, considering the bags under his eyes and he just passed out right after having his Smash essence extracted 

**Rush Smash**

\- Extracted essence created the Dog Fullbottle

\- The eleventh Smash; unlike the other Smashes, this one was completely quadrupedal, making it resemble the Fullbottle it created, and it was very agile on its legs; because it was lower to the ground, it was tough aiming attacks at it 

\- The Rush Smash, as its names suggests, mainly attacked by using rushes and tackles rather than anything fancy, so we were lucky that besides it being lower to the ground and its slightly superior speed to Build, defeating it wasn't too bad 

\- Using RabbitTank was really all I needed to beat the Rush Smash; that, and using a Refrigerator-powered Vortex Break to freeze it in place helped set up the Vortex Finish, probably the easiest Smash fight I had in a long while

\- Victim was a girl with dog ears (almost thought that they were cat ears, but when Misora purified the Fullbottle I realized what they really were)

**Screen Smash**

\- Extracted essence created the TV Fullbottle

\- The twelfth Smash; out of all the Smashes I faced so far, this one probably got my pity the most

\- The Screen Smash really doesn't have much going for it; its large screen-like head being able to shoot large powerful beams would be a threat, if it didn't take forever for it to charge, that it couldn't _move_ while it was charging, nor redirect the beam _while_ it was firing it; all in all, using just a Vortex Finish-powered punch from LionCleaner was all that was needed to allow it to be purified of its Smash essence

\- Victim was a slightly overweight man with square, dirty glasses with thick lenses and really wavy messy hair; he even looked a little pitiful

**Call Smash**

\- Extracted essence created the Smartphone Fullbottle

\- The thirteenth Smash; while also not necessarily a powerful Smash, it was a little infuriating to deal, even with All Might and Izuku being around to help out

\- The Call Smash, like the other recent Smashes, while not particularly physically strong, did have a unique power; in this case, it could call on for help from surrounding Guardian troops that functioned basically like the ones that organization stole; it had gathered a giant group of them before we came to stop it

\- Using GorillaRobot really helped out plow through the Smashes with the super strength provided by Gorilla and Robot, though it didn't compare at all to All Might's; with him around, we were able to cut down the number of Guardians to a more manageable number that All Might could deal with them himself and I could focus on the Smash, which was easy to take down with a GorillaRobot Vortex Attack before finishing with a LionCleaner Vortex Finish

\- Victim was a gal who's first instinct was to look for her phone before passing out 

**Long Smash**

\- Extracted essence created the Giraffe Fullbottle

\- The fourteenth Smash; not a very fancy Smash, but still troublesome no less

\- While not the most physically impressive Smash, its does have a powerful neck that can extend and retract within seconds; combined with its horns, it was a challenge to face. It also had hoof-like hand coverings that added some extra power to its punches

\- Taking the Long Smash down was simple enough; just used RabbitTank as usual to fight, used a Lion-powered Drill Crusher to weaken it, and finished it with a RabbitTank Vortex Finish

\- Victim was a middle aged man with a Quirk mutation that turned his head and neck into that of a giraffe's (must be hard for him to get into buildings)

**Needle Smash**

\- Extracted essence created the Hedgehog Fullbottle 

\- The fifteenth Smash; another easy to defeat Smash (seriously, I think that organization might be struggling to find ones that were as strong as some of the earlier ones; that, and I'm just getting better) 

\- The Needle Smash could generate a lot of spikes from its body, as well as its fingers, but it seemed a lot slower than one might assume, which was its folly, really

\- RabbitTank was all that was needed really to beat this Smash, and a few extra speedy strikes with a Rabbit-powered Drill Crusher allowed me to deal much more damage in a shorter amount of time; was completely surprised that the Vortex Break was all that was really needed to weaken it enough for me to extract the Smash essence

\- Victim was an ordinary guy; not much to really say about him besides his like, piercings and mustache 

**Notes for the Chapter:**

> \- I'm gonna be buffering every two to three future chapters (initially it was gonna be the end of each chapter, but it was making the third chapter way too long, so this is how I'm gonna do it) with extra tidbits and junk, like stuff about the Best Matches, Fullbottle effects, Smash files, and more (including the stuff that's been done off screen). In universe, the notes are probably a lot more detailed and thorough than what I'm providing. Think of this as a summary of what they could've possibly wrote for their stuff.  
> \- "Why the Vortex Finishes given names"? That will tackled in the next chapter.  
> \- I was having a hard time deciding whether or not to use Faust or Sento as the "writer" for the Smash Files. Both have valid ideas and stuff, but in the end I went with Sento since I think having Faust would be a little more spoilery in some regards. I'll make a "Faust Special" version for the Build Files when I feel like the time's appropriate for it.  
> \- If you're familiar with Smashes, the Fang Smash is an official Smash, but its short description is not necessarily the same. That's because it's one of those "it has the same name, but isn't the same" sort of situations. The Fang Smash was basically a reuse of an existing suit, so I figured it'd need its own version.  
> \- Yea, I also changed the Ice Smash to be the one who gave the Refrigerator Fullbottle. While it is cool that the Smashes that the Fullbottles came from didn't necessarily look like the things the Fullbottles came from, it didn't necessarily always work for me, which is the reason for the change. Also, just the Fang Smash, the Ice Smash is different, though in this case, just slightly.  
> \- With that, yea, expect a lot more original Smashes and some alterations to the canon Smashes.  
> \- Technically, each Smash entry would have a date, but I don't wanna bother trying to come up with an official timeline, because I am terrible with that unless it's an original work. I'm just gonna say that the Smashes before the Explode Smash happened within the past two months before the start of the story. Well I do one-shots focusing on these off-screen Smashes? Maybe, but considering how fast they're often defeated by Build and the other Riders in his season, and how fast I kinda finish the fights, I don't necessarily think the fights would need full chapters.  
> \- Why doesn't Sento try out all the possible Fullbottle combinations to find the appropriate Best Match? My justification in my fanfic is that he's far more busy working in the Institute, working on weapons (like he's still stuck on making the HawkGatlinger since he wants to make it stylized after the Best Match than just the Fullbottle its connected to), fighting Smashes, and trying to figure out the mystery behind everything happening. As smart as he is, there's only so much he can really do on his own. Sure, he's got Izuku, Misora, All Might, Souichi, and Ryuga now to help, but he's still got some limits (for now). Also, he's overthinking about how Best Matches work, so the simple answers don't work for him.  
> \- Something I realized was that Sento was leaving people behind after he extracted their Smash essence. In my canon, he sends texts to the proper authorities that there are people that need help (anonymously of course) and leaves before they come.  
> \- If you're thinking that I'm making fun of nerds with the Screen Smash, don't worry; the guy I'm describing is me, so it's just a little self-depreciation at my expense. That's about as far as a self-insert I'll do for this fanfic (I do have an idea for an avatar character if I ever feel like using it, but likely chances are I'm never using them for anything serious).  
> \- I'll talk about the Rock, Sting, and Antler Smashes in the second Build Files, since their Fullbottles haven't been purified yet, whereas the Needle Smash's was. I'll be doing that for other Smashes too if their Fullbottles haven't been purified by the end of the chapter.


	5. Chapter 4

**Summary for the Chapter:**

> Sento's team grows, while Ryuga tries to deal with life.

**Notes for the Chapter:**

> Sento Kiryu: Last time on "Building a Hero!", Izuku Midorya learns more about Build from the genius scientist Sento Kiryu, who has taken All Might's apprentice as a lab assistant, as they work together to solve the mystery behind the organization and its leaders! 
> 
> Izuku Midoriya: From what Mr. Kiryu had taught me, I learned about the powers of the Fullbottles, the Build Driver, and tech! 
> 
> All Might: What's more, I learned that one of my old high school chums, Souichi Isurugi, was Sento's beneficiary! And that Lil Misora is the one responsible for providing Mr. Kiryu the Fullbottles!
> 
> Ryuga Banjo: What is this?
> 
> IM: The recap for the last chapter.
> 
> AM: It a way for our audience to stay up to date, as well as provide a form of entertainment! 
> 
> RB: Seems a little frivolous if you asked me.
> 
> SK: Oh, and that's the murder convict Ryuga Banjo, who I so mercifully saved out of the goodness of my heart from being kidnapped by three Smashes at once that were created by one of the members of the organization, Meta Bolt, after he spent some time crying about it. 
> 
> IM: Indeed, as it turns out, Mr. Banjo was taken from the prison he was kept in by the organization and put through the same experiment as Mr. Kiryu and I! 
> 
> AM: Not to mention that he revealed to me some startling information that my good friend Tsukauchi wasn't even present at the interrogation about the murder of Takumi Katsuragi! What could this possibly mean!? Found out, in this chapter of "Building a Hero!"!
> 
> RB: I wasn't crying!
> 
> SK: You responded way too late for that.

"Seriously, Sento? _Another_ guy who you revealed your secret to?" Souichi said, rubbing his temples after taking him aside to give him a stern talking to. Ryuga, for the most part, was just in the workshop poking around. He was also given new clothes, since the white cotton ones he had been wearing were dirty and torn up. "And not just that! It's Ryuga Banjo, a murder convict!"

"Well what else should I've done? Let him get arrested again and experimented on?" Sento said, casually brushing it off. "Murderer or not, and I'm thinking not, he's Midoriya's and my best bet to finding out where the organization is. He managed to escape from there, with his memories intact. So if we just jog his memories a bit, we can find out about these guys and why they keep making Smashes!"

Sento watched as the pieces clicked in Souichi's head, and the two rushed over to talk to Ryuga. "Can you start from the beginning?" Sento said, looking Ryuga straight in the eyes. "Tell us everything." 

"The beginning? Okay," Ryuga said, taking a deep breath and sitting down. "I was born in Yokohama, a healthy 3.2 kilograms-"

"Not that far back!" Sento said, smacking Ryuga in the head with a rolled-up piece of paper. 

"You said from the beginning!" 

" _You_ should've figured from the context clues and situation that that's not what I meant!" 

"Well I-" 

The argument was cut short when the Purification Chamber's made a ringing ding that echoed through the workshop, startling Ryuga, while Sento's characteristic giant grin spread across his face and a cowlick sprung up from his hair. "Finally!"

He rushed over to the Purification Chamber's microwave, and pulled out two new Fullbottles. The first was a light blue that was shaped like a diamond, and the second was yellow that was shaped like a bee. 

"So we got Diamond and Bee, huh?" Sento said, going over the two newly acquired Fullbottles. "Oh, I am feeling good about these ones!"

Misora, for the most part, walked out of the Purification Chamber, yawning as she repeated her mantra. "Tired... Sleepy... Want my money, Sento... I'll finish the last one later..."

"Who are you!?" Ryuga said, looking at the Purification Chamber and pointing at the tired girl who just came out of it. Misora, for the most part, just gave him a powerful stink eye before squaring up to him, surprising Ryuga who just backed up in response to the short girl threatening him.

"I should be the one asking that..." she said, exhausted. She made it past him and her father, and went into her room, closing the door shut as a loud thud came from her room, no doubt her collapsing onto her bed out of exhaustion. 

"Just what's going on?" Ryuga muttered, when the minifridge entrance opened, and All Might walked into the Build Shop. 

"Sorry about that, everyone," All Might said, adding in a laugh. "Would've been here sooner, but Mr. Himuro wanted to check up on me to make sure I wasn't injured!"

"Aaah, All Might!" Ryuga said, squaring up to prepare for a fight. All Might simply laughed, and shook his head. "Don't worry, Banjo. I won't turn you in! At least, not yet. It seems like you have a connection to the organization behind all the Smash incidents, not to mention what you said earlier has peaked my interest. Now, if you don't mind, I need to make a personal call. Mr. Kiryu, can I borrow your bedroom?" 

"Sure, go for it, All Might," Sento said, as All Might walked over into the hallway and entered Sento's room, closing it. 

"Man, who would've thought that All Might would've been working with a crazy vigilante?" Ryuga muttered, watching him disappear. 

"I'm not crazy," Sento said. "And the reason why he's working with us, is that we have the same goal of finding the organization behind the Smash incidents. His apprentice is just like us, he was experimented on, and wants answers about what happened."

"All Might's got an apprentice?" Ryuga said, when the entrance opened again, and Izuku came down the stairs. 

"I got those Smash victims away safely, Sento," he said, as he shifted his gaze between Sento and Ryuga. "So... we're really doing this? I-I mean, not to say that what the organization had done isn't bad, but this is Ryuga Banjo, a convicted murderer-"  
  
"I didn't kill anyone!"

"Holy crap it's that murderer!" 

Everyone looked at the stairs, and saw the former Rock Smash standing on it, with the former Bee Smash behind him and the former Antler Smash closing and locking the entrance. 

"What the- Midoriya, you were followed!?" Sento said, while Souichi sighed exasperatedly in the back. "I know there's been a string of people finding out who I am, but even I have a limit!" 

"I-I didn't! I kept checking behind me to make sure that I wasn't!" Izuku said, panicking at the revelation that he was followed.

"We didn't," the pink girl said, apologetically, when she pulled out a business card. "You dropped this, and we looked up the address, and when we got to the window we saw you coming down here. We just wanted to thank the Kamen Rider for saving us."

"What!?" 

"Oh no, that's right! I kept a copy of cafe nascita's business card in my pocket to remember the address!" Izuku said, realizing his giant blunder. "I should've just kept it on my phone!" 

"This place is _super cool_! I wish my place had a secret lair like this," the horned girl said, mildly oblivious to the situation. 

"Argh, this is getting too much to handle," Sento said, as he went to sit on the couch. "Alright, let's just get this over with. My name is Sento Kiryu, and yes, I'm Kamen Rider Build."

"I-I'm Izuku Midoriya," Midoriya followed, still embarrassed about his blunder. 

"I'm Ryuga Banjo, and I'm _not_ a murderer," Ryuga added, crossing his arms.

"Souichi Isurugi, and I need a drink," Souichi said, muttering as he went to the kitchen area and pulled out a couple canned coffees. 

"Oh, uh, I'm Eijiro Kirishima," the boy said, pointing to himself. 

"I'm Mina Ashido! Me and Eijiro have been classmates, since like, we were little," the pink girl said, cheerfully.

"And I'm Pony Tsunotori! I just moved here from America a few weeks ago, and I didn't think that I'd go _crazy_ like that," the horned girl said, laughing a bit. 

"So, what do you guys want to know? I'll answer as best as I can," Sento said, rubbing his temples. "I'll admit, this isn't how I expected my day to go. Probably can't get any worse than this-"

"Dang it, come on! Open up you stupid door!" 

Everyone froze, and looked up. "Oh lord, were you three followed!? Come on!" Sento said, climbing up the stairs. 

"No, we weren't! We kept looking to make sure," Eijiro said, as everyone followed him. The sight they saw was definitely not something they expected, as a paper-thin woman with short wavy hair had gone under the door's crack, struggling to open the lock with her thin fingers. 

"Oh, uh.... hi, Build?" she said, grinning. "I'll admit, this isn't the entrance I wanted, it was gonna be much more dramatic than this..."

"Okay, who are- wait, you're that reporter from last night," Sento said, as he started to recognize her. "H-how did you know where to find me!?"

"Oh, you dropped this," the reporter said, slipping her flat hand into a pocket in her jacket, and pulling out a crinkled business card. "After you detransformed and called those officers, remember?"

"W-what!? I don't carry business cards on me! Why would-"

"Oh, right," Souichi said, as a realization came to him. "I put that in your jacket so that you could advertise cafe nascita..."

"Owner!" Sento said, appalled.

"My bad!" he replied, putting his hands together. 

"Um... can you open the door for me, since we all established that I know about you now?" the reporter said, still fumbling with the door's lock. 

"Alright, but first, tell me who you are, and what you want," Sento said, crossing his arms. 

"Well, my name's Sawa Takigawa, and I'm a freelance reporter," the paper-thin woman said, sticking her flimsy hand out to shake. "As you can see, my Quirk's, well, Elasti-body."

* * *

_**Sawa Takigawa! Quirk, Elasti-body! It allows her to flatten, stretch, and do all kinds of elastic-y things with her body! Combine that with her job as a reporter, it lets her do a lot of sneaking around! Just don't expect her to be able to infinitely stretch, shapeshift into different things for too long, or have any dexterity while she's flattened!** _

* * *

"... Nah, not doing that," Sento said, going back down. "I'm already in trouble with the media, why would I let that happen?"

"Wait, come back!" Sawa said, flimsily waving him to come back. "I promise you, I won't reveal your identity! Please, I really need a story! The past couple months haven't been that great," Sawa said, pleading. "Besides, I won't be like those reporters who've been besmirching your good name!"

"... Fine, but I'll need to look through your articles and notes and edit them so I won't have you like, revealing too much about me or my team. There's a lot we need to keep secret," Sento said, looking at her as he unlatched the door, letting Sawa into the Build Shop as she inflated herself back to normal. 

"Alright, I'll explain as much as I can later, but I need to ask Banjo something. Do you remember anything particular happening before you were kidnapped from the prison?" Sento said, returning his attention to Ryuga. 

"Nothing really. I was busy moving some boxes when some fat guy with a big horn came from behind and hit me with a handful of like, sleeping powder," Ryuga said. "That was some powerful stuff, too. Only really got a glimpse of him before I went unconscious. Probably could remember him accurately if I saw a picture of him or something."

"I think I can do something about that," Sawa said, smiling. "I'm good at snooping around, so I'll find some info without any trouble. Now, tell me about everything you can about your role as the Kamen Rider and the Smashes..."

* * *

All Might sighed, punching in the numbers to his friend Tsukauchi's cellphone. There was a commotion going on outside the room, but he decided that it wasn't too important to pay attention to. After all, they did bring in a "murderer" into the Build Shop, of course there would be trouble. Still, what Banjo said earlier troubled him. Months ago, when he was arrested, All Might tried asking questions about him, and was told that Tsukauchi was there and it was all taken cared of, and that he didn't need to worry. So hearing otherwise by the felon himself was a blow.

Plus, it had been some time since their last chat, so the idea of asking him about it never crossed his mind until now. 

"What is going on..." he thought, as Tsukauchi picked up. "All Might, it's been a while! Sorry I haven't called you in a while, been picking up some suspicious dealings going around, and with Ryuga Banjo on the loose, it's been pretty hectic here. How've you been?"

"Oh, I've been fine," All Might said, chuckling. "Been taking it slow. Finally found a successor, so I've been training him on my off-time. Speaking of Ryuga Banjo..."

"Yea, I heard about it from the officers that were there, about how you chased the Kamen Rider and Ryuga but got attacked by some Guardians when you landed on them by accident and got distracted by them letting the two escape. So sorry about that, gotta ask Namba Industries to take care of that problem."

"Yes, well, there's that, and well... Something Ryuga Banjo said has bothered me..."

"Really? Must've been something serious if it's gotten you upset, All Might."

"Indeed. I was told by another officer that you were there at his interrogation, but when I mentioned how your Quirk revealed the truth, he said that there wasn't a Tsukauchi there. Is... is that true?"

The other end of the line went dead silent. All Might clutched his chest, fearing what Tsukauchi would said next.

"Is that what you were told? That I was there? I wasn't."

A pit in what's left of All Might's stomach fell. "I was personally told that there was already enough evidence of Ryuga Banjo being Takumi Katsuragi's murderer and that I wasn't needed to help out. That's troubling." 

"And that's why I called you on your personal phone, to make sure that you weren't being listened to," All Might said, his left hand curling his fist. "It's just as I feared... something bigger's going on in the background, much more than I thought at first..." 

"Hm... I'll help you as much as I can, but if there is something going on within the police force, my hands are going to be tied. Not to mention this _is_ hearsay based on a convict's words, so that will be trouble on its own," Tsukauchi said. All Might sighed. He figured as much, but he needed confirmation from Tsukauchi if he really wasn't present for Banjo's interrogation. 

"Thanks. I'll keep an eye out for Banjo either way. We'll get to the bottom of this, I promise," All Might said, clutching his fist. The two said their goodbyes, and hung up. He pinched his forehead, as he thought over the situation once again as the complexities have gotten worse. The Smash incidents, the organization behind them, their victims, and now apparently they have connections to the police, since they seemed to have taken Ryuga Banjo from prison and used him for their experiments as well. Not to mention that they told him and Tsukauchi different stories. It was a good thing that their friendship wasn't known at all, or else they'd have never known about this discrepancy. 

Still, it didn't sit well with him at all, the thought that even the police were involved. Who knew how far this organization's hands reached? There could even be government officials participating in this, and the thought that these people would be eager to throw away the lives of their civilians was sickening. 

His thoughts were interrupted when the commotion outside got louder. With voices he didn't recognize. He decided to muscle up, in case if there was any trouble brewing outside. 

* * *

"So this machine and some girl help make your Fullbottles?" Eijiro said, looking at the machine. "And you make them from those essences you take from Smashes?"

"Yep, you're taking this pretty quickly," Sento said, smiling, though it turned into a frown quickly. "Unless that knucklehead."

"I'll understand if you let me go!" Ryuga said, struggling against his chains. On the suggestion of Souichi, he had been chained to one of the pillars, since the others were a little uncomfortable with him walking around. "This isn't cool!" 

"Hahaha! What is going on out here?" All Might said, coming out of the room. Everyone excluding Sento, Souichi, and Ryuga froze at the sight of this. 

"All Might's here!?" Eijiro said, his eyes wide. Mina, for the most part, just sat there, mouth agape. 

"He's in on this whole Kamen Rider biz?" Pony said, almost giddy with excitement. 

"Oh man, this scoop's getting better! At least, it would be if I could reveal more about it!" Sawa said, scribbling down notes as fast as she could. 

"Um..." All Might said, looking at Sento. 

"Dropped business cards," he said, plainly. 

"Huh," All Might said, looking at the four newcomers. "Well, despite my grin, I can't say I'm totally happy with this predicament! Mr. Kiryu and I have agreed that, in spite of our positions as the Number One Hero and the vigilante Kamen Rider, it is in our best interests to figure out what is happening with the organization behind the Smash incidents, as they have taken my apprentice and experimented on him as well! So this needs to be kept quiet! Think of this as a... secret mission!" 

"Wait, 'apprentice'?" Eijiro said, thinking for a bit before he looked at Izuku. "You're All Might's apprentice!?" 

"Y-y-yes, I am," Izuku said, smiling nervously. "I-i-it's just circumstantial, we meet when he saved Bakugo and me from that sludge villain-"

"Wait, you're that kid that rushed in at that sludge guy months ago?" Mina said, gasping. "No wonder I thought I recognized you from somewhere!" 

"Wow Midoriya dude, you're way _cooler_ than I thought!" Pony said, pumping her fists. 

"So I'd take it that you're Sento's apprentice, too?" Sawa said, writing it down. "This is getting better and better!" 

"Hey hey hey, like I said, don't write everything down without my approval," Sento said, pulling her notepad away to look over it. "You can write that... not that... this is alright... nope... nada... fine. But like All Might said, you all can't be blabbing about this to anyone. We've kept this whole operation under wraps for a long time, and it isn't like we're telling you all this because we want to. I need you all to promise me that you won't, alright? Especially you, Miss Sawa." 

"Of course you can trust us!" Eijiro said, slamming his fists together, before flinching and wiggling his hands for a bit. "Oh right, temporary Quirk loss..." 

"Yea, that's gonna be tough to explain to my parents," Mina said, looking at her hands and feet. "On the plus side, no need to worry about accidentally ruining my favorite clothes or shoes for a few days."

"D-don't worry!" Izuku said, trying to smile. "When it comes back, it'll be better than ever! You could probably do things you couldn't do before even!" 

"I dunno," Eijiro said, scratching the back of his head. "Don't know how getting harder would be like..."

"Yea, and stronger acid? Doesn't necessarily sound good for a hero, you know?"

"Ooooh, do you think it'd make my horns bigger!? I'd love to have bigger horns to fire with!" 

"Well, we'll see about that when they come back," All Might said, giving them a reassuring laugh. "So I take it that you're all going to go to hero school then?"

"Oh definitely! I'm planning to go to U.A.! It's the best of the best, and I figured that I should aim for the top, even if I'm not nearly as flashy as others!" Eijiro said, grinning widely. 

"Me too! I figure that with U.A., I'd be able to figure out more ways to use my acid without needing to worry about hurting people!" Mina said, making finger guns and pretending to shoot them. 

"And I want to go to U.A. to learn how _kick butt_!" Pony added, doing a high kick and hitting the pillar with the restrained Ryuga.

"Hey hey hey, watch it!" he said, as he ducked his head to avoid the hoofed girl's feet. The group laughed a bit, before Izuku looked at the clock.

"Whoa, it's getting late, I got to get going," Izuku said, as he picked up his bag. 

"Yea, same. My parents are not gonna be happy hearing about my Smash-ification and stuff," Eijiro said, nervously laughing. 

"Oof, mom's probably gonna flip, too," Mina said, grimacing. 

"My parents will probably just spoil me silly," Pony said, bonking her head with her right fist and sticking out her tongue. "Since I'm the only one in our family aiming to be a hero and all." 

"Yea, you guys better get going," Sento said, scratching the back of his head. "I don't want you guys to spend too much time here when you're all students."

"Don't worry, we'll come back first chance we get!" Eijiro said, getting pumped. "I want to stop those jerks from doing this to other people!"

"Yea, go Team Build!" Mina said, pumping her fist into the air. 

"'Team Build'?" Sento said, quirking his eyebrow. 

"Yea, since you're Build, and you got Mr. Isurugi, his daughter, Midoriya, All Might, Miss Takigawa, and us as your team, we're Team Build!" Mina said, grinning. 

"Hm... I like it! Team Build it is!" Sento said, puffing out his chest in pride. 

"Wait, what about me?" Ryuga said, his brow wrinkled. "Why am I not a member of Team Build?"

"Um, uh, well, uuuuuuh-"

"I think it's 'cuz you're a criminal?" Pony said, as Mina nodded to confirm.

"I didn't do anything wrong!" 

"You keep saying that, but there isn't any proof otherwise..." Eijiro said, scratching his head. 

"I'll show you all! Just let me go and I'll prove it! Somehow!" 

"Banjo, let it go. People need time to get to trust you, don't try forcing it. Just relax for now," Sento said, patting him on the head, a little condescendingly. "Just think about stuff that makes you happy."

Ryuga opened his mouth to interject, but closed it and sighed. "Now, with that settled, you all need to get going."

The members of Team Build all said their goodbyes, and went up the stairs, though All Might was the last one to go. 

"Mr. Kiryu, I need a word with you for a moment," he whispered, looking at him. "Make sure that the others are gone before I leave, since I can't go through the door with my muscles like this."

"Alright, we'll talk in the kitchen supply closest," Sento said, immediately understanding the urgency in All Might's voice. "Just stay here, and I'll make sure they're gone."

* * *

"Hm... so your friend Tsukauchi, who has a lie detecting Quirk, wasn't there at Banjo's interrogation, but yet that was what you were told?" Sento said, after All Might told him everything. "And he was told that there was enough evidence to implicate Banjo for Katsuragi's murder?"

"That's right," All Might said, having released his muscle form minutes ago after the confirmation that everyone was gone. "But because my friendship with Tsukauchi isn't known, even to the chief of police, I don't think they counted on giving conflicting stories to the two of us. It took me some time to find out though, since it's been a while since either of us had any free time to talk to one other."

"I can't believe it, with this information, it just confirms that there are governmental agents involved with the organization," Sento said, scowling a bit. "First, someone must've committed Katsuragi's murder and pinned it on Banjo to get him arrested. Second, they used their connections to the police to make it so that he could be taken to jail, where they then kidnapped him to experiment on."

"But why now? Why not the moment he was arrested?" 

"Probably to avoid suspicion. High-profile murderer sent to jail, only to mysteriously disappear the second he was there? The question really is why him in specific? What makes Banjo so special that they had to go through all that trouble? I mean, thinking about it now, some of the kidnapped people they used for the experiments must've been prisoners. That way, they could go under the radar without anyone noticing."

"That doesn't explain why they've taken to using regular civilians and heroes-in-training, though," All Might said, clutching his fists.

"Hm... it is possible that those ones are just because their Quirks are more impressive," Sento said, his hand to his chin in thought. "There have been some really unimpressive Smashes before, and the toughest ones I've faced tend to be the ones who have their eyes in the hero business." 

"So we have to keep an eye out for the youths, then? Those _bastards_. To think, the people that are supposed to be helping protect citizens are involved in this monstrosity!"

"Don't worry, we'll get them soon and make them pay. Your tip really helped out, All Might. While Tsukauchi's hands might be tied in how he can help, it's enough that we know to be a little more wary of the police, as much as I hate to say that," Sento said. "We just got to keep doing what we've been doing for the past few months; you fight to protect the people as the Number One Hero, and I fight to protect the people as the vigilante Kamen Rider." 

All Might nodded, knowing that this was going to be the best they could do for now. And with Ryuga Banjo as their lead, they'll need his help more than ever now. 

* * *

Izuku stared at his phone, looking through the new numbers that were inhabiting it. Eijiro's, Mina's, Pony's, and Sawa's were now all on it, having exchanged them so that they could talk to each other more (though with Sawa, probably not as much considering how much older she was than him). 

"This is the first time I've gotten the numbers of people my age," Izuku thought, since his old friendships pretty much ended before he had ever gotten a cellphone. "But am I really their friend? We only got to meet because they were turned to Smashes, and I'm not sure if that's really a good case to be friends-"

His thoughts were interrupted the moment his cellphone sprung to life by vibrating in his hands. He checked it, and saw that he had gotten a message from Pony. He opened it, and saw that it was a group message between not just the two of them, but with Eijiro and Mina as well. 

* * *

**rodeo_poneo:** hey u three!

 **all_might_jr:** Pony? What's with the message?

 **red_riot:** nice username midoriya, figured you'd go with something like that, being all might's apprentice

 **all_might_jr:** I'm planning to change it. Had it for a long time before becoming his apprentice, it's kinda embarrassing now.

 **asshidity** : i think it's cute

 **rodeo_poneo** : _totally_!

 **all_might_jr:** I digress. So why are you sending a message to all of us?

 **rodeo_poneo** : i just wanted to get to know you all better, since being turned into smashes probably isn't the best relationship starter, ya dig?

 **asshidity** : yea, i can see that. i mean, we're all on team build now, so we should get to know each other better!

 **red_riot** : i can get behind that!

 **all_might_jr** : Alright, but let's not mention that too much, since our texts might get recorded and everything.

 **rodeo_poneo:** oh that makes sense

 **asshidity:** yea definitely

 **red_riot** : can't let that happen

* * *

Izuku chuckled as he texted Pony, Mina, and Eijiro back and forth. It was nice, having people his age to talk to for once. Sure, Mr. Kiryu, Misora, and All Might were all great, but he was still a lot younger than them, so it was good change of pace for him. He learned about Eijiro's own admiration for the old hero Crimson Riot, Mina's love for dancing, and Pony's family life (like how her brother was apparent a death metal singer and her mom was a model). He went to bed feeling pretty good about himself, since he finally found some people who were like him. Maybe this whole "Team Build" thing and getting experimented on wasn't so bad after all. He had a pretty good feeling about everything. 

* * *

"Come on, let me go," Ryuga said, still chained to the metal frame pillar. He had been there all night, as Sento, Misora, and Souichi had all gone to sleep without untying him. 

"I'll let you go after I come back from work," Sento said, as he grabbed his phone from his workbench. "Until then, Misora's gonna be teaching you about how the Fullbottles, Smashes, and the whole purification process, since the Owner's gonna be at his second job. Seriously, how long will it take for you to get it?"

As Sento went up the stairs, Misora came out of her room wearing thick rimmed glasses and holding a chalkboard with drawings and writing and a ruler, appearing as if she tried to dress as a teacher, but she was still in her pajamas, just with a yarn coat over them. "Alright, class is in session," she said, smirking. 

"Ooooh, come on," Ryuga moaned. "First you tied me to this, and now you're torturing me?"

"Hey, this is all a visual aid to help you understand. I figured you'd be the type of person who'd understand more from visual teaching. And be glad I'm doing this out of my own free will," Misora said, crossing her arms. "I bet you that a lot of my fans would love to see me dressed like a teacher."

"What?"

"Nothing. Anyways, this is how it goes," Misora said, holding the chalkboard up and began to point at it with the ruler, though Ryuga grabbed it with his feet, and started to read it outloud, since it kept moving around too much for him to understand.

"Organization makes the Smash by using gas on victims... Smash-ified victims go on a rampage until Build stops and fights them... Build takes the essence using an Empty Bottle which makes it into a Smash Bottle... Build takes the Smash Bottles and has them purified into Fullbottles," he said, as he followed the diagram that Misora drew up.

"See? Now you're getting it. And the main way the Smash Bottles get purified is by me, using my bracelet and the Purification Chamber," she said, pointing at her bracelet and then at the Purification Chamber, when her phone's notifications went off. She took it out of her pocket and checked it, when Ryuga started to get an idea. 

"Seriously? That's how Fullbottles are made? By you?" he said, sneeringly. "I don't think so."

"You saw me get out of that Chamber yesterday after the Diamond and Bee Fullbottles were purified."

"Hm... I don't think so. After all, I didn't _see_ you make it, I just saw you come out. Besides, how could a tired shut-in like you could do that? I bet that you're just saying that 'cuz you're full of yourself."

"Oh, you want proof?" Misora said, a little incensed by his disbelief. "I'll show you. You're gonna owe me a lot of money after seeing this." 

Misora put her phone down and got up to grab the Antler Smash Bottle from the workbench, and placed it inside the microwave part of the Purification Chamber before opening the door to it. "Just you wait and see, Banjo," she said, before the door closed shut. When he confirmed that the door was closed, he reached for her phone with his feet, and, with surprising dexterity, pressed numbers into it before pushing the call button and leaned towards the phone as close as he could. 

"Kasumi? Kasumi, are you there?" Ryuga said, hoping to hear her voice. It had been forever since he heard her. They hadn't let anyone visit him in the facility for some reason, and it killed him that he couldn't see her. 

"Ryuga!? Ryuga is that you!? Help me, please!!!" the voice on the other side cried.

"Kasumi!? What's going on!? Kasumi!" Ryuga said, as panic settled in.

"Ryuga Banjo..." a new voice said. It was modulated and garbled, though nevertheless had a sinister intonation to it. Ryuga felt like he heard this voice before, but he wasn't sure. "If you want to see your girlfriend again, come to the address texted to you. It might be the last time you'll ever get to see her."

The call ended, and Ryuga shook with fury. The organization had clearly taken Kasumi as a way to get to him. But he couldn't just sit there and do nothing. Not when she was in danger. Mustering all the strength he had, Ryuga started to push against his chains, straining until they finally broke. He grabbed Misora's phone, watching as the location the man mentioned popped up in her text messages, and he looked around to see what he could use to get there, and saw another phone on Sento's workbench, this one resembling the one that could turn into that motorcycle he would use. Next to it was that Phoenix Fullbottle from the day they met.

"That will do," he muttered, grabbing the two of them, and he rushed upstairs and out of the Build Shop. He was coming to save Kasumi, consequences be damned. 

* * *

Sento was typing away at his work computer, reading all the data and observations that had been recorded about the Pandora Box as fast as he could in order to catch up to the other scientists. So far, it wasn't too much to go on, though that's to be expected with unknown alien technology. Even the metal wasn't an alloy found anywhere on Earth (someone came up with the name "Pandorium", and while that was a useful name, it sounded more like it involved pandas than anything), but that whatever the Box was made for, it was capable of generating a great deal of energy. But for what, now that was the mystery everyone was stuck on. 

"So how're you adjusting to the workload, new guy?" a plain-faced coworker, Eita Kawai, asked, as he handed him a coffee mug. "I've heard about how much you wanted to work on the Pandora Box Observation and Testing Team, but really, there's not much to find for now."

"Nonsense, this is fantastic!" Sento said, smiling. "To think, that we have evidence that there was life on Mars at one point! Though that does beg the question of what the Pandora Box could be used for..."

"Personally, I think it might've been just a generator," a bird-faced coworker, Shinga Kuwata, interjected, typing away on his computer with his feathered fingers. "It's what Katsuragi told me before he was fired, and he was a genius, so he was probably the one who's right on track."

"That's Katsuragi's theory?" Sento asked, raising an eyebrow. "Makes sense, though what kind of generator would make something like the Skywall?" 

Before anyone could come up with an answer, Sento's phone started ringing. "Hello?" Sento said, picking it up. "He WHAT!?... Okay, yea... I'll head over soon."

"Sorry, an emergency came up," he said curtly, getting up. "Dog escaped... My sister and her friends are really, really panicking, so I need to head out to help search. He's a real, real important dog, too."

"Do you really think you should-" Eita began to say, when Gentoku entered the room. 

"What's going on?" he asked, looking at the three of them.

"Dog escaped, and my sister and her friends need my help to find him," Sento said.

"Hm... normally, I wouldn't let any of my scientists leave early, but considering how much you've been helping the Institute since you've came, and the fact that you've proven yourself to be one of, if not the, smartest people here, I figure I can give you some extra perks," Gentoku said, patting Sento's shoulder. "Just be back here for the rest of the work day when you're done."

"Thanks, I promise I'll be back as soon as I can!" Sento said, putting his overcoat on and rushing out. 

"Hey boss, can I have some extra perks? I've been here like, since the beginning," a scientist asked, looking at Gentoku.

"I dunno, have you made any new progress on the Pandora Box yourself? Or on other old experiments?"

"No..."

"Then there's your answer."

* * *

The school day had come and gone for Midoriya, and he went to the train station to meet up with All Might when he got a call from Misora.

"Midoriya? Thank goodness I got you," she said, sighing. "Listen, Banjo escaped while I was purifying the last Fullbottle you guys got."

"What!?" Midoriya said, accidentally getting stares from some nearby bystanders, reminding him to speak in whispers. "How did he? He was chained to that pillar."

"Well, he broke through the chains while I purified the latest Fullbottle, so he's a lot stronger than he looks. If you were wondering, it's the Deer Fullbottle. Don't worry, I already called Uncle Toshi and Sento about this, and they're on their way to capture him. Kirishima and the others found out when they got here, so they're off to try and help, too. I figured that with you being Uncle Toshi's apprentice and all, that you'd want to help out, too. I'll send you the GPS location, since he took my personal phone, that jerk." 

"Thanks, I'll call you later when we get him," Midoriya said, and as they hung up, he got Ryuga's location, and started to make his way over there. "What's going on with you, Mr. Banjo?"

* * *

Ryuga drove as fast as he could on the weird smartphone-motorcycle that Sento had built (seriously, how did that work?), passing by countless people (thank goodness he was wearing a helmet that obscured his face and all). The guys who had taken him had Kasumi in their grasps, and it aggravated him. It was infuriating how they were using his girlfriend to get to him like this. It wasn't fair, she didn't do anything wrong. If anything, all the "problems" she's caused for him have been made by others. He took a deep breath, as he remembered everything that had went wrong in his life like it were yesterday.

* * *

_"That's right, sir! It was all him!" Breaker Box said, pointing to Ryuga. He had just clocked in that day, so he had no clue what was going on. He just saw some bigwigs from the Hero Boxing Association talking to his boss and some of his other coworkers. "He's the one that's been rigging boxing matches!"_

_"Wait, what?" Ryuga said, pointing to himself. "I haven't done anything like that!"_

_"Don't lie!" Big Blue, one of the other sidekicks, said, crossing his arms. "You told me that you needed money for your girlfriend's medicine, so I've been throwing my matches so you'd get some money!"_

_"Me too!"_

_"Same here!"_

_"It was all Banjo's idea!"_

_"I haven't done anything like that! It's true that my girlfriend needs medicine, but I wouldn't-"_

_"Mr. Banjo, with all due respect, all of the evidence we've gathered about this match rigging had led to you. Not to mention, it's their word against yours," one of the bigwigs said, robotically (since that's what his Quirk made him look like, Ryuga supposed). "We have no choice but to revoke your boxing license."_

_"Wait, you can't do that-"_

_"We'll also have to ask that your hero license is suspended as well, since we don't think having an ex-boxer who broke rules isn't hero material," another one of them said, pushing up her glasses. "We've already contacted the hero offices about that, and they agreed to do so."_

_"But I haven't even-"_

_"Consider your career postponed, Mr. Banjo," the robotic bigwig said, as they walked out. "We won't be seeing you anytime soon again."_

_Banjo stared at the ground. It all happened so fast, and he didn't even have the chance to defend himself. The dream job he had been working for, gone in an instance._

_"Sorry about that, Banjo," Breaker Box said, putting a 'reassuring' hand on his shoulder. "They were getting close to finding out about our group and I, so I had to make you the fall guy."_

_"Wait, so you've really been-"_

_"Yea, and I promise you, I'll send you a big paycheck to make it up to you soon. You're a real big help-"_

_"I don't care about the paycheck!" Ryuga snapped, making everyone back up a bit. "I always wanted to be a boxer and a pro hero, and now my chance is gone! Do you have any idea how hard I worked for this-"  
_

_"Yea, and trust me, with your Quirk, you really didn't have too much of a chance in either of those," Breaker Box said, flippantly. "I did you a favor by making you a fall guy. But like I said, I'll send you a big paycheck for this. Or you can choose to not take it, and not be able to pay for your girl's medicines. What will it be, Ryuga?"_

_Ryuga gritted his teeth, knowing that any money he'd get, whether he liked it or not, would be helpful for Kasumi. So he reluctantly stuck out his hand, and shook Breaker Box's with it._

* * *

_"Ryuga, are you alright?" Kasumi asked, as Ryuga looked through all of the job ads on the table. "You should take a break, you know, and relax a bit-"_

_"I'm fine, Kasumi," Ryuga said, putting up a smile. "Just a little frustrated, you know. I've been job hunting for weeks now, and I still haven't find anyone that'd take me on."_

_"... I'm sorry about what happened."_

_"Kasumi, don't say that. I already told you, it's not your fault."_

_"But they still used me to pin all of that match rigging on you," Kasumi said, biting her lip. "Maybe... maybe if I ask my dad for some money, he'll-"_

_"We will not go to your dad," Ryuga said firmly. "You've already told me how much you don't like him, and I don't like him that much either. I'll think of something..."_

_Ryuga turned back to his job ads, clutching his forehead in thought as he scanned each ad over and over again. "You know what, you're right. I think I could take a break. Wanna go on a picnic?"_

_Kasumi smiled a bit, when her phone rang. "Hold on, I'll take this. Go ahead and pack some food, I'll be ready in a few minutes."_

_After a train ride to Kasumi's favorite cherry blossom tree and setting up the blanket and food, Ryuga took a deep breath as he laid down on the blanket while Kasumi walked around the tree. Despite the rocky last couple months, he could still smile while Kasumi was around._

_"Hey Ryuga!" Kasumi said, surprising Ryuga by dumping a bunch of cherry blossom petals onto his head. "I got some great news! You know that phone call from earlier?"_

_"Yea?"_

_"Well, it was about a job opening! It was an assistant position for a scientist named Takumi Katsuragi. Apparently he heard about you, and a friend of his asked me to tell you about it!"_

_"Really?"_

_"Yea. Isn't that great?"_

_"It is, but it's kinda weird. What would a scientist want with a former pro hero boxer sidekick like me?"_

_"You don't want it?"_

_"Nah, I'll take it, just wondering how he found out about me? Oh well, I guess I can just ask him when I come."_

_"Great! Now let's get back to our picnic, shall we?" Kasumi said, her smile continuing to brighten up Ryuga's day. "It's not everyday we get to see this ol' cherry blossom tree bloom, isn't it?"_

_"Don't worry, even if we missed it, we can just come back and watch it again, right?" Ryuga said, raffling Kasumi's pink hair. The two laughed, as the petals flew around them._

* * *

_The next week, Ryuga had left earlier than usual, since the address he was given was quite a distance away from where he lived. "This is the right apartment..." he muttered, knocking on the door._

_"Hey, Mr. Katsuragi? It's me, Ryuga Banjo. I'm here about the assistant position your friend called my girlfriend about," he said, waiting for a response. Nothing. He knocked again, and twisted the door knob. To his surprise, it was unlocked. "Mr. Katsuragi? I'm Ryuga Banjo, and I-"_

_Ryuga froze. There, on the ground near the couch, was a dead man who was stabbed in the back, blood oozing out. Before he had a chance to process what was happening, a troop of police burst into the room, pointing their guns at him._

_"Ryuga Banjo, you are under arrest for the murder of Takumi Katsuragi!"_

* * *

It was still unbelievable to think that he was just set up like that. As he entered another abandoned factory, a troop of Guardians popped out of nowhere to stop him. "Halt, you are trespassing on private property. Leave at once, or be punished."

"Sorry, but I got places to be!" Ryuga cried out, trying to weave through the pillars in hopes that it'll confused the Guardians. It didn't, and they shot in front of him, forcing him to come to a screeching stop. "Crap!"

As the Guardians surrounded Ryuga and prepared to capture him, Build came screeching in on his motorcycle, tackling some of the Guardians out of the way before pulling out his weapon and inserting a white hedgehog-shaped Fullbottle into it. 

" **Ready, go! Vortex Break!** "

Build pointed his weapon, and fired a series of needle-like projectiles at the Guardians, knocking them back before grabbing Ryuga. "What are you thinking!? You're wanted for a crime! What would make you come out of the Build Shop in the first place!" 

"You wouldn't understand! They got Kasumi!" Ryuga said, punching a few Guardians away from him. Build shot a few more Guardians, before finally processing what Ryuga said.

"'Kasumi'?" he said, after they finally got rid of all the Guardians in the building. "Who's Kasumi-?"

Suddenly, they heard a commotion going on outside, and the two rushed outside to find a new troop of Guardians. The troop came to a stop, and before their eyes, they watched as the troop began to come together, and formed a giant bipedal tank-like robot. 

"Huh, that's new..." Build said, looking at the giant robot. "No matter, nothing that Build can't handle. Let's try out glistening muscles!" he added, pulling out the Fullbottles in his belt and replacing them with Gorilla and Diamond. " **Gorilla! Diamond! Best Match!** "

"A Best Match? Yes! Let's do it!" Build said, cranking his belt. Two new runners formed, with the brown Gorilla Halfbody forming in front, while the light blue Diamond Halfbody forming in the back. " **Are you ready!?** " "Build Up!"

The runners slammed together, forming Build's new armor. Replacing Rabbit's red was Gorilla's brown, his left eye resembling a gorilla flexing its massive left bicep, while his right arm now had a massive armored fist with a piston attached to it, and an armor plate resembling the right pectoral muscle rested above Build's real one. Tank's blue was replaced with Diamond's lighter blue, with a diamond-like shoulder pad, and three gem-like decorations on the left side of his chest armor. " **The Shining Destroyer! GorillaMond! Yeahhh!** "

"Now I've found-" Build began to say, when All Might came from the sky, and landed nearby. "Never fear, for _I AM HERE_!!!"

"New threat detected; commencing arrest," the giant Guardian robot stated, aiming its guns and firing at All Might, but this left it opened to an attack by Build at its legs. 

"Hey, Mr. Number One!" Build said, as he started to smash through the Guardian's leg. "Seems like this thing's defective and going after people it shouldn't! Mind if we take it down?"

"No worries!" All Might said, leaping on top of the Guardian and pulling off its guns. "This Guardian feature seems more dangerous to the everyday civilian in the first place! I'll have to ask Mr. Namba and Mr. Himuro about removing this for the sake of the people!" 

Together, All Might and Build made short work of the combined Guardian robot, tearing it apart like tissue thanks to the sheer strength of the Number One Hero and Build's newest Best Match, showcasing its power to convert things into diamond with Diamond's BLD Prism Glove and breaking them apart with Gorilla's Muscle Glove. Ryuga ran inside, watching them ripping it apart, and got back onto his motorcycle and prepared to drive off when Izuku and the three other teens came in.

"Don't take another step!" Eijiro said, trying to be threatening, though without his Quirk he couldn't really do much to back it up. 

"Yea! Escaping like that really wasn't smart of you!" Mina said, also trying to be threatening. 

"You'll have to go through us!" Pony said, mimicking a karate pose. 

"Mr. Banjo, why did you leave the Build Shop like that?" Izuku asked, his fists clenched. It was clear he didn't want to fight, but he was definitely ready if it came down to it. "Not only are you wanted by the government, you're wanted by the organization behind the Smash experiments! We can't help you if you recklessly-"

"Shut up!" Ryuga said, silencing all of them. "You don't understand, they got Kasumi, I need to-"

"Then explain to us, so we can understand you."

Ryuga turned around, and saw Sento and All Might approaching him from behind. "You have people around you that can help, so why not ask for it?" All Might said, laughing. "After all, that's what we heroes do!" 

Ryuga looked around, trying to figure out a way to leave without anyone following. When it became clear that there were no such openings, he sighed. "Fine. Alright. That organization took my girlfriend, Kasumi, and gave me an address to go to. I need to be there, so I can save her. But I need to do it myself. This is my problem, and I need to solve it myself-"

"Why, all the more reason that we need to help!" All Might said, smiling, though it was straining behind all the anger he was feeling. "After all, a hero's duty is to stick his nose into problems that they're not involved in!" 

"All Might's right," Sento said, walking to Ryuga. "We'll help you out. After all, you're our lead to the organization, and it's not like the Kamen Rider can refuse to let something bad happen to anyone, either!" 

"... Thanks," Ryuga said, as he got on his bike. "Don't know about the kids, however. It might be dangerous."

"Indeed. I think you four should stay behind for your safety," All Might said. "We'll come back for you soon="

"Are you kidding? We want to help!" Eijiro said, as the other three nodded in agreement. "Besides, being involved with Team Build, we're already kinda breaking the law, so why just let us sit out on this?"

"All Might, I'm your apprentice, and I've been at yours and Mr. Kiryu's side since the three of us met, I don't think this time would be any different," Izuku said, bringing up a good point to the senior hero. "At this point, I think it's my duty to observe what's going on!" 

"Alright, you do bring up a good point. However, like usual, if the situation escalates, I'll take you and the other three out of the area as fast as I can," All Might said, conceding to Izuku's point. "So let's start heading to the location. Can't keep Mr. Banjo's lady waiting too much longer!" 

* * *

Ryuga drove in front of Sento, leading the others to the location that was sent to him, which was an empty construction lot surrounded mostly by forest and some errant buildings. He looked at a nearby apartment building, and realized where they were. He and Kasumi had been looking at those apartments to move into right before he lost his licenses, which had put their plans on hold. Before he could ruminate on his thoughts for much longer, something had thrown fireballs into the apartment building, setting it ablaze.

"Those apartments!" Mina shouted in horror, as more fireballs flew into it. 

"I'll handle it!" All Might said, letting go of the four teens. "You four stay back! Don't get involved with saving Ryuga's girlfriend or following me! That's an order!" 

The four teens nodded in agreement, and All Might leaped off, rushing as fast as he could as firetruck sirens went off in the distance. As soon as All Might left, however, fireballs flew into the construction lot, forcing them to run. Ryuga turned around, and saw a Smash approaching them. Its head was a huge, bulbous ball with holes all over it. Its shoulders were equally as large, resembling grenade-like structures, and its right arm resembled a flamethrower. 

"So it was a Smash throwing those fireballs. Guess we'll call this one the Burn Smash with that in mind," Sento muttered, putting the Build Driver on. He took out his Rabbit and Tank Fullbottles, when the air began filling with sinister laughter.

"This isn't your ordinary Smash, Kamen Rider," a voice said, as the group looked around. A gas cloud appeared behind the Smash, and when it dissipated, a man in black had appeared. He wore silver armor with pipes sticking out of it like exhaust ports, with bat-wing like blades on his gauntlets. His chest armor had a yellow bat insignia resting on it, while his visor matched it.

"The bat man!" Izuku shouted, as they steeled themselves. The bat man stared at them for a bit, processing what he just called him, before chuckling. "Night Rogue, actually."

"You..." Sento said, staring him down. "You're the one who took my memories!" 

He slammed the Fullbottles into his belt and started cranking the handle. " **Rabbit! Tank! Best Match! Are you ready?** "

"Transform!" he cried out, as the runners with the Rabbit and Tank Halfbodies formed. They slammed onto him, and he rushed towards the Burn Smash and Night Rogue, swinging his fists at them. " **The Moonsault of Steel! RabbitTank! Yeahhh!** "

"Nuh uh uh, Kamen Rider. You should calm down. After all, you might just hurt poor miss Kasumi here," Night Rogue taunted, stunning Build, which allowed the Burn Smash to throw another fireball into him, knocking him back. 

"That Smash... is Kasumi?" Ryuga said, falling to his knees. His chest grew heavy, and his eyes started to water. "No..."

"It's alright! I'll just extract the essence!" Build said, replacing Rabbit with Hedgehog. " **Hedgehog! Tank! Are you ready?** " "Build Up!" 

Rabbit's red was soon replaced with white, and Build's shoulder armor became spiked. On his fist was a boxing glove-like armor that was also spiked, and his left eye changed shape to resemble a white spiky hedgehog. He ran towards the Burn Smash and Night Rogue, though he had taken out his gun and shot the ground. "Do that, and she'll die." 

"What? What do you mean?"

"Tell me, have you ever encountered a Hazard Level 1 Smash?" Night Rogue asked, freezing Build in his place. 

"Hazard Level 1?"

"Of course you haven't, my organization and I don't normally use them for a good reason. The subject's weak constitution offers zero resistance to the dose of Nebula Gas they're exposed to. Within seconds of Smash-ification, the host dies, their body and soul dissipating. What you're fighting right now, is basically a zombie," Night Rogue said, to everyone's horror. "Normally I'd avoid using anyone determined to be a Hazard Level 1, but taking the suggestion of my cohorts, I figured that this should be the exception. After all, Ryuga Banjo needs to be punished for running away."

"No way," Eijiro said, staring at the Burn Smash.

"It's too late?" Mina said, covering her mouth.

" _Oh no_..." Pony said, as she looked between Ryuga and the Burn Smash.

"Kasumi..." Ryuga said, tears streaming from his eyes. Izuku, for the most part, was silent. He never realized that there could be people who would die from being turned into Smash. His fist curled, but before he could say anything, Build screamed in fury, and rushed towards Night Rogue.

"Tch, you're gonna have to do better than matching random bottles to beat me," Night Rogue said, dodging each punch. He materialized his blade, and started parrying Build's attacks.

"How dare you," Build growled, as sparks flew between their weapons. "People aren't just yours to experiment on and throw away!"

"Like you'd understand what I'm planning. I'll do whatever it takes for my goal, and if that means sacrificing a few people, so be it," Night Rogue said, knocking Build back. "I think we're done here. You can clean up that mess, Kamen Rider."

Before Build could retort or get up, Night Rogue swung his gun, creating a gas cloud that covered him. "Remember this, Build. There's no such thing a world without sacrifice," Night Rogue finished, before he disappeared. Build looked around, and returned his attention to the Burn Smash, who surprisingly had been docile for a while. In fact, it seemed to look like it was struggling to hold back, as fire spewed out of its arms and shoulders. 

"Is... is she holding back?" Build said, watching the Burn Smash struggle. To his shock, the Burn Smash started to strike itself, aiming its fire towards it and avoiding everyone around it. "She should've lost any resemblance of control or personality... is her love for Ryuga helping her?"

"Kasumi, please, open your eyes," Ryuga said, sobbing. "Didn't we promise to stay together? That we'll go back to that cherry blossom tree you love? I wanted... I always wanted to be better for you... So please, stop..."

The Burn Smash stared longingly at Ryuga, fire erupting from it, before standing up, and opening its arms. Its breaths were heavy, and it seemed to struggle holding its position. 

"Do you... want me to extract your Smash essence?" Build said, as the Burn Smash seemed to give a resemblance of a nod, before losing control again and launching fireballs again, though they didn't hit anyone. Build glanced over to Ryuga, who seemed to realize that there was no other way to save her. 

"Kiryu... please... stop her," he choked out. Build simply nodded, and switched out his Fullbottles. " **Rabbit! Vacuum! Are you ready?** "

As the Burn Smash fired more fireballs, Build stuck out his Long Range Cleaner, sucking them in and storing them in his Trash Converter. He pressed the button on his chest, releasing the fire into a vortex above him. He took out his Fullbottles, and swapped them out for Gorilla and Diamond. " **Gorilla! Diamond! Best Match! Are you ready? The Shining Destroyer! Yeahhh!** "

Once the runners encased Build in his GorillaMond armor, he started to crank the Build Driver's handle, preparing for a Vortex Finish. " **Ready, go! Vortex Finish!** " 

He pointed to the fire vortex above him, converting the flames into diamonds that spun in a vortex, which he pointed at the Burn Smash. The diamond vortex picked the Burn Smash up, spinning and dealing as much damage as it could while lifting it into the air. As it floated in the air, a glowing woman was separated from the Smash, landing beneath it. Build took notice, and rushed underneath the vortex, blocking it and the Smash from landing onto her.

"Kasumi!" Ryuga cried, as he rushed to her side. He looked up to Build, who was clearly struggling to hold the vortex and Burn Smash above them. 

"Sorry, this is all that I could do on short notice!" Build said. "If you need to say anything, say it now!" 

"Ryuga..." Kasumi said, as she stared at her lover. "I'm so sorry... your life... your life must've been so troublesome because of me..." 

"Kasumi, don't say that... I already told you, none of it was your fault," Ryuga said, struggling to hold his tears back. He caressed her pink hair, and wiped the tears that were flowing out of her crystal blue eyes. "You were the best part of my life, Kasumi. You've always been."

"But your license revocations... and that fake job offer... and the money you spent on my medicine... all of it happened because of me," she said, her breaths growing short. "I shouldn't have trusted that man... Nabeshima... I should've known that it was too good to be true..." 

"It's alright, Kasumi, it's alright," Ryuga said, hugging her tightly. "None of it was your fault. None of it... The life I had with you, I'll do it all over again! So please, don't go... don't go..."

"I'm sorry, Ryuga," she said, morosely, as she looked at her hands, which were dissolving into light. She knew that she was running out. "I think... I have to..." 

She glanced over to the four teens, who were too stunned to see this side of Ryuga. "You four... I know it's selfish of me to ask... but can you watch over Ryuga for me? I think... I think he could use all the friends he can get... I love you, Ryuga... So please... please move on, for me..."

Kasumi closed her eyes, and went limp, her body finally completely dissolved into light. Ryuga sat there, trembling as he watched the light float to the sky. "But... we promised... to see your favorite cherry blossom tree bloom next year... we promised..."

Once Build saw that Kasumi disappeared, he knocked the diamond vortex and Burn Smash away, finally finishing the Vortex Finish. The Burn Smash laid there, motionless, allowing him to extract the essence with no problem. Once he finished, there was no trace of the Burn Smash or Kasumi left. As Build took off the Build Driver, everyone stood there, trying to process what happened, when All Might landed nearby.

"I am here!" All Might said, but before he could laugh, he noticed everyone's downtrodden faces. "What... what happened while I was gone..."

"All Might..." Izuku said, as he struggled to spit out the words choking him. "Ryuga's girlfriend... she... we..."

"It's alright, my boy," All Might said, lowering himself to assure Izuku. "You all don't need to tell me what happened right away. I... I can surmise what happened... Mr. Kiryu, what shall we do now?" 

"... We head back to the Build Shop," Sento answered, walking over to Ryuga. "Get up, Ryuga. We need to go before any Guardians or police officers get here..."

"... Leave me alone," Ryuga said, as he curled into a ball. "Kasumi's gone... there's nothing left for me... I don't care anymore, it's fine that-"

"It's not fine!" Sento said, pulling Ryuga up to look him in the eye. "Nothing about this is fine! But you heard what she said... She said to move on..."

"How can I move on, when she's gone!?" Ryuga barked, pulling his arm away. "I can't just forget about her! I just can't-"

"Moving on doesn't mean to forget her, Ryuga. It just means that you have to live on, for her sake," Sento said. "So you should move on, and live for her. You don't need to forget her, but that doesn't mean you should stay stuck in the past, lamenting her forever. And I promise you, we'll take down the organization for what they've done. They won't get away with this."

Ryuga stared at Sento, and silently got up. The two walked over to the motorcycles, and put on their helmets before driving off, and All Might soon picked up the teens, and leaped after the motorcyclists. 

* * *

Once they made it to cafe nascita, Ryuga and Sento went down into the Build Shop, while the teens and All Might sat in the cafe. He had been informed about Night Rogue, the nature of people with a Hazard Level of 1, and the fate of Ryuga's girlfriend Kasumi. Silence had befallen the room, as everyone struggled to figure out what else to say. 

"All Might," Izuku finally said, looking at his mentor. "Has there... has there been anyone you couldn't save, no matter how hard you tried?" 

All Might looked at his young protege, as he struggled to find the right words to say. "... Yes, of course. As the Number One Hero, I try my best to save as many people as I can. But regardless of how many I save or how often, there will always just be that one where circumstances won't allow me to. Be it that I wasn't nearby, or was occupied, anything. A hero's life is a tough one, and as much as I want to save everyone, I know that it's just not possible. That's why I'm Number One, so I can inspire others to help where I can't be. I am but one person, so I hope that there are others who are willing to take it upon themselves to do good where I'm not."

"... Back there, I was so helpless," Izuku said, clutching his fist. "All I could do was just stare... I couldn't fight Night Rogue, I couldn't save Miss Kasumi... I couldn't do anything meaningful..."

"It's not fair!" Eijiro said, as indignation got to him, and he stood up in anger. "We were right there, and we couldn't do anything! We couldn't... we couldn't do a single thing..."

"... I want to get better," Mina said, firmly. "I want to get so good, that Night Rogue and his friends would think twice before Smash-ifying anyone else ever again."

"Same!" Pony said, trying to get back to her gung-ho attitude. "Those guys won't mess with anyone else after we stop them in their tracks!" 

"I need to get better, and I need to get better soon," Izuku said, getting up. "I can't call myself your apprentice if I can't save anyone that's right in front of me like that! I just can't..."

"Now that's what I like to hear," All Might said, laughing a bit before checking the time. "I should leave soon, I'm sure that they're wondering where I am at my office. Take care, young heroes."

The teens said their farewells to All Might, and as he left, the four teens shifted their gaze to the minifridge door. "I guess... we should check up on Mr. Banjo," Izuku said, walking and opening the door as the other four followed suit. 

* * *

After spending some time to himself in his room (thank god they finally gave him a place to sleep in), Ryuga came out, and saw Sento sitting in a chair facing the Purification Chamber. "Hey, Kiryu... Thanks for what you did earlier today. I know that there wasn't much that you could to save her, but I appreciate you for giving me that chance to talk to Kasumi one last time... I know I don't know much, but I'll do my best to help you and those kids out with finding the organization. After all, my beef with them is bigger than ever now."

He looked at Sento, who sat there, still. "Um... Hey, I'm thanking you for what you did today. Are you seriously going to-"

Ryuga walked around to face Sento, only to notice his eyelids were closed and he was softly snoring. "He's asleep!?" 

That's when the Purification Chamber went off and those four teens came down the stairs, surprising Ryuga. Sento, on the other hand, sprung awake, and a tuft of hair stuck out of his head and a manic grin spread on his face. "The new Fullbottle's done!" he said, rushing over to the Purification Chamber.

"Seriously?" Ryuga muttered, staring at Sento with disbelief. "You and those Fullbottle things, I swear..."

Sento opened the microwave door, and pulled out the new Fullbottle, only to be slightly perplexed by it. "A dragon?" he said, as he ran his fingers over the dragon image on the blue Fullbottle. "Is it because of Ryuga's name..."

Misora walked out of the Purification Chamber, and looked to Sento, not saying a word, before redirecting her gaze at Ryuga, who had gone to sit on the couch. Sento followed her gaze, and realized what she was thinking. "Hey, Banjo, take this," he said, tossing the Fullbottle to him. "Since it was made with Kasumi's Smash essence, I think you deserve to hold onto that."

"Really?" Ryuga said, glancing at Sento before fixing his gaze onto the Dragon Fullbottle.

"Yea, thank of it as her love for you. She loved you so much that it created this Fullbottle," Sento said, scratching his head. 

"Kasumi..." Ryuga said, holding the Fullbottle in his hand tighter. 

"Are you sure about that? I mean, you haven't tested it yet and-" Izuku began to say, but Sento stopped him.

"It's alright. I think that it'll be in good hands for now," Sento said, sighing. "Besides, I'm not feeling any Best Matches with Dragon for now."

"Mr. Banjo?" Pony said, looking at Ryuga. He picked his head up, and stared at her. "I'm... sorry for misjudging you."

"Yea, me too," Eijiro said, as Mina nodded in agreement. "We were so caught up in thinking about you being guilty, that we didn't realize that you were still, well, a person."

"... It's alright," Ryuga said, sighing. "I just... so much happened within this past year or so, and I... I dunno, it's hard to really say."

"Can you tell us about her? About Miss Kasumi?" Mina said, as she sat down on the ground, intent on hearing his story. Before he had the chance to answer, Sawa came walking down the stairs, smiling. 

"So it might have taken a while, but I found out information about the man who might've taken Banjo to be experimented on. Out of the thirteen guards that were on the clock while looking after Banjo, only one matched his description. One Masahiro Nabeshima," she said, producing the photos and information she scoured to Sento and the others. Ryuga got up, and snatched the photos from her. "That's him! That's the guy that shoved that sleeping powder in my face!" 

"'Nabeshima'... Ryuga, that was the name that your girlfriend mentioned! The one that said he had a job for you!" Izuku said, as he remembered the last words Kasumi had said. 

"Nabeshima..." Ryuga said, seething as he gritted his teeth. 

"Looks like we're finally getting somewhere," Sento said, as the others smiled, as they finally got some good news. "And it all starts with Nabeshima!" 

**Notes for the Chapter:**

> \- Hey guys, sorry that this took a while. A lot of things happened. My dog died of old age at the beginning of August, and I took some time to myself to grieve. Then my family went on the week-long vacation we've been planning before that, so that also took a lot of my time. But after this, I'm planning on going back to trying to stick to the schedule I planned out for myself.  
> \- After I finished my vacation, I decided that I'll be sharing "Building a Hero!" and any related stories that come out of it to [Spacebattles](https://forums.spacebattles.com/threads/building-a-hero-my-hero-academia-x-kamen-rider-build.780313/), since I want to try and get some more engagement with the story.  
> \- I know I mentioned that I would explain why Build has names for his Vortex Finishes in this chapter, buuuuut I ended up kinda forgetting about that while writing this chapter, and before I knew it, there wasn't really any space to give an explanation about that. Oh well, next chapter for sure.   
> \- I hope that the string of people joining Team Build doesn't feel too forced. I always wanted those three particular characters to join first out of Class 1-A and 1-B, and I kinda wanted it to be early.   
> \- Next chapter will be kind of a breather, with the characters going over some of the revelations and such. At least in the beginning.


	6. Chapter 5

**Notes for the Chapter:**

> Eijiro Kirishima: Last time on "Building a Hero!", me, Mina, and Pony got to meet the infamous vigilante Kamen Rider Build, Sento Kiryu!
> 
> Mina Ashido: Not totally on purpose, mind you, we were just following the address on the card, since we got a feeling that Midoriya knew something about him. 
> 
> Pony Tsunotori: But it got even _crazier_ when it turned out that the Number One Hero All Might is Mr. Kiryu's ally! And even Ryuga Banjo, who turns out not to be as much of a bad guy as we thought! 
> 
> Sawa Takigawa: And I'm getting the biggest scoop of my life!
> 
> Sento Kiryu: Hey hey hey, remember you can't tell everyone about everything. There's a lot of things we need to keep secret.
> 
> All Might: Hahaha! That's right! For instance, it would be in poor taste if the Number One Hero was seen openly gallivanting with a vigilante, even one as necessary as Build! 
> 
> ST: Right, right, of course. 
> 
> Izuku Midoriya: And the organization behind the Smash incidents kidnapped Mr. Banjo's girlfriend Kasumi and turned her into one. But because of her weak constitution, she died the moment she changed, and when Build extracted the Smash essence, nothing was left.
> 
> Ryuga Banjo: Well gee, thanks for putting it like that. 
> 
> IM: Sorry Mr. Banjo...
> 
> Misora Isurugi: But it's not all gloom and doom. When I purified her Smash essence, it turned into the Dragon Fullbottle, a symbol of her love for Ryuga. 
> 
> SK: And thanks to her and her dying words, we've at last found a new lead. Nabeshima, the man who orchestrated Banjo's arrest and kidnapping for experimentation. Will we discover what this organization is? What is Nabeshima's role in all of this? Let's find out in this chapter of "Building a Hero!"

"Alright, let's all review this one more time, because _someone_ can't seem to grasp the whole thing in spite of being the one involved," Sento said, staring directly at Ryuga. Sento was standing in front of the glass board, which was covered in a complex flow chart. Ryuga, Izuku, Eijiro, Mina, and Pony were sitting on the ground in front of him, while Misora was sitting on the couch, exasperated by the fact that this explanation had been going on for hours now, and Sawa was off at the corner, painting her toenails. 

"First things first, Banjo was framed at Breaker Box's agency for match rigging. While this might seem unrelated, it's the first step in the chain. Then, after weeks of unemployment, a man named Nabeshima contacted Banjo's girlfriend Kasumi about a job opening as an assistant to Takumi Katsuragi, a scientist from the Institute. Banjo accepted, only to find Katsuragi murdered in his apartment, where he was immediately arrested, in spite of very little evidence proving it was him. And after a few months at the facility he was kept at, Banjo was sedated and kidnapped by Nabeshima, and experimented on by the organization behind all the Smash incidents, meaning that Nabeshima is our best lead to finding out just what this organization is, and their ultimate goal. If we find out more about them, we'll find out why they took Banjo, Midoriya, and I to be experimented on, and why our memories, or more precisely, mine, are missing. Now, is that clear?" Sento said, pointing to each diagram drawn on the board as he went over it. 

"Hm... I think I finally got it!" Ryuga said, as the others sighed a breath of relief.

"Not like we're really any closer, though," Misora said, shaking her head. She got up, showing the papers and photos Sawa had brought to the Build Shop. "I tried the contact information we had gotten, and it turned out to be bogus. Both the address and phone number were fake."

"Wait, what!?" Sawa said, as she finally finished her last toenail. She sprung up, and grabbed the papers. "But I went through so much trouble to get these!" she said, falling to her knees. Misora stared at the despairing Sawa, and sighed. "Well, I think I can fix that for you, but you're gonna have to pay me." 

"Huh?" everyone, excluding Sento and Izuku, said, staring at her with confusion. 

"Dad!" Misora called, as Souichi came down the stairs. "It's idol time," she added, deadpan. 

"Of course!" Souichi said. In a flash, he grabbed a portable changing stall and a set of clothes from behind the TV. Misora stepped into it, and pulled it up. Clothes flew out from above it, with Sawa covering Ryuga's eyes, Mina covering Eijiro's, and Pony covering Izuku's, while Sento just looked the other way. As this happened, Souichi set up a tripod with a camera pointing where Misora was standing, propped up a cute backboard on the opposite side, and pulled down the changing stall.

To everyone's astonishment besides Souichi and Sento, Misora had instantly changed from her cute pajamas to a checkerboard-shirt, with a overall decorated in buttons and stickers, a bunny-ear headband that hung around her neck like a big bow, fuzzy wristbands, a pair of oversized headphones, and a big top-hat bow holding up her ponytail. 

"Hi! It's me, Miitan!" Misora said, with an amazing amount of energy that the group hadn't seen before from her. A giant goofy grin was plastered on her face, which she immediately squished with her fingers. On the computer, it showed her surrounded by a few display boxes. 

"Misora's a popular net idol, y'know," Souichi said, with an air of overinflated pride. "She's got thousands of fans across Touto, Seito, and even Hokuto! All of them help Misora gather info, you see. Idol fans can be crazy like that." 

"A net idol?" Ryuga said, mildly intrigued as he walked towards the camera, though he was pulled away by the others, preventing him from ruining the shot. 

"I can't believe it! She's the request-making idol that no one ever sees in person! Miitan!" Sawa said, pulling out her camera and snapped a few pictures of her. "Gotta get some glamour shots for the future..."

"Misora's Miitan?" Eijiro said, confused. "I didn't realize that... She's so... different in person."

"Yea, honestly I kinda wanted to meet her myself, but I didn't think she'd be so... tired sounding most of the time," Mina said, raising an eyebrow. 

"Yea, even now I still can't believe it," Izuku said, grimacing a little bit. "Even though I've seen this dozens of times now..."

"Do you think she'll sign an autograph for me? My little sister _loves _Miitan," Pony said, watching as Misora danced in front of the camera. 

"Now for today's request! Ta-da!" Misora cheered, as she motioned to the side with both her hands. On the screen, a picture of Nabeshima popped up. "Can you guys look this man up for me? A fan of mine sent me this, saying that their life depended on finding him! So could you do the same for me? Please?"

Misora spun around so quickly that the camera didn't catch it, but she had a small eyedropper in her hand that she squirted into her eyes. She walked up to the camera, "tears" in her eyes. "Pretty please?"

"How did she do that?" Eijiro asked, impressed with how fast she did it. 

"Practice," Sento muttered, when the computer's notifications began beeping like crazy. 

"Oh? Looks like one of you saw one of those _scaaaaary_ Smashes over at a park! To "MiitanLove" who sent the info, thaaaank you! Kisskiss!" Misora said, as she shaped her hands into a heart. 

"And that's my cue to go," Sento said, grabbing his Build Driver and his overcoat. "I'll be back soon."

"Oh, I'll come with you! I need to get some shots of you as Build!" Sawa said, as she finished taking her last picture of Misora and followed Sento. 

"Wait, what?" Ryuga said, walking after the two. "What about finding Nabeshima? Don't you remember what you said? About getting your memories back?"

"This and that are two different things," Sento said, shrugging. "Besides, this is a more pressing matter."

"How is this Smash attack more pressing than anything we're going through!? What's really more important, saving ungrateful strangers as Build or your memories!?" Ryuga asked. Sento paused, but said his answer without hesitation. 

"That's easy, Build."

* * *

At the Touto Capital, Gentoku stood at the side in the conference room, watching his father engage in the monthly meeting between the three countries' Prime Ministers. It was all pointless, really. The other two Prime Ministers were the most stubborn and bullheaded people Gentoku had ever seen.

"Today marks the tenth anniversary of the Skywall Incident," Touto Prime Minister Taizan Himuro said, pushing his glasses up as he looked at his fellow Prime Ministers. "Are things going well in Hokuto?" 

"Oh, the childcare programs and agricultural projects are finally bearing dividends, Himuro," Hokuto Prime Minister Tajimi Yoshiko replied, giving him a grin that was a bit too wide to be genuine. She rapped her talon-like fingers on her chair. "Though I have the feeling that our Seito friend might ridicule me for focusing on internal affairs."

"Oh, don't worry about that," Seito Prime Minister Mido Masakuni answered, chuckling a bit, and flashed a smirk that showed off his fang-like teeth. "While my focus is on sending our young adults across the world in order to support our economy, I would never insult how you two handle your countries, even if I disagree with your approaches."

"So I take it that neither of you want to take a unified approach as a country, then..." Prime Minister Himuro said, seeing the tense postures his fellow leaders had. 

"Not for the foreseeable future, I think," Prime Minister Masakuni answered, bluntly. "Not with so much vital infrastructure still divided thanks to the Skywall."

"I have to agree," Prime Minister Yoshiko added. "As long as that wall's there..."

"Fair enough," Prime Minister Himuro said, looking to the side, almost grumbling. "Then I'll see you all at next month's scheduled meeting."

As soon as Prime Minister Himuro finished his sentence, the holograms of Masakuni and Yoshiko disappeared, leaving him and Gentoku alone in the room. Himuro looked at the empty chairs in the conference room, and sighed. After all these years, these two have not budged one bit on their stances.

As he walked out of the conference room, Gentoku followed him to the stairs of the second floor. "I need to tell you something. I've been hearing rumors that Hokuto is assembling an army that's comparable to Seito's, and-" 

"Not this again," Himuro said, pinching his forehead. "Over and over, you keep suggesting that the other countries are planning to wage war, but there's no proof for that."

"That might be, but I still think we should build our army-"

"No need. Touto only needs enough strength to defend ourselves. Nothing more, nothing less." 

"But father-"

"I thought I asked that when we're here, that you call me Prime Minister," Himuro said, sternly. "More importantly, have you found out anything about the Kamen Rider?" 

"... No."

"Hm... troubling. It's been almost six months since he publicly appeared, and over that time he's been causing unrest within our civilians," Himuro said, stopping to take a breath from walking up the stairs. "He needs to be captured so that peace can return in Touto." 

"Right, of course," Gentoku said, though he stroked his beard a bit more thoughtfully. "Though I think we could use that technology of his to-"

"Don't even think of such a thing, Gentoku," Himuro said, cutting him off. "Having that sort of technology is bad enough in the hands of one man, we shouldn't be attempting to arm more with it."

"Yes, yes, that would be bad," Gentoku said, agreeing with his father. But as his father went into his office and closed the door, he muttered to himself, "Bad for Seito and Hokuto, maybe..." 

* * *

This afternoon had gone south for Kouta. He had been at the park with his mom as an award for passing yesterday's math test, when some weird cloud bullet thing hit his mom and turned her into one of those Smashes he's heard about on the news. She was chasing him mindlessly, flying and shooting weird pellets at him. 

"Mom! Stop!" he pleaded as he ran, before stumbling onto the ground. Before his mom could attack him again, Kamen Rider Build rushed by him, and stopped her attack with a powerful punch. 

"Huh, a Smash capable of flight... guess we'll call you the Flying Smash to make it simple, since you're a bit... nondescript," the Kamen Rider said, looking at Kouta's mom. It was true. Her Smash form had a weird airplane-shaped head, but her arms were flat and wide, with weird silver claws on the ends. "Go under the bridge, kiddo, I'll make sure your mom will be alright." 

Kouta nodded, and ran towards the bridge and behind a pillar. He was soon joined by Sawa with a camera hanging around her neck biking at a breakneck speed. "Finally! I made it!" she muttered, nearly out of breath, but she composed herself quickly enough to set up a tripod camera and started to record.

"There's no telling what formulas and equations are going on in Build's head right now!" she said to the camera, as Build and the Flying Smash exchanged punches. The Flying Smash pulled away, and started to fly off to get some distance between them.

"Oh, don't think you can get away that easily! Let's you escape a strong suction!" Build said, pulling out the Rabbit and Tank Fullbottles and replacing them with the Gorilla and Vacuum ones. " **Gorilla! Vacuum! Are you ready?** "

"Build up!" Build announced, as the red of his armor was replaced with brown, and the blue replaced with teal. "GorillaVacuum! What an unexpected combination!" Sawa said, while Kouta watched with amazement. "But will he say his catchphrase!? Will he!?" 

"I've found the-" Build began to say, but was interrupted by Sawa.

"The winning formula!"

Build sighed, seemingly a bit exasperated by Sawa's excitement. He shook off that exasperation, and started to pull in the Flying Smash using the Long Range Cleaner. 

"Look at all that sucking!" Sawa said, as the air around them tugged at them a bit towards Build. "He's using the vacuum's sucking power to keep the Smash from flying away and to reel it in!" 

As soon as the Flying Smash was within his range, Build jumped towards it, and punched it with the powerful Muscle Glove. "And he hits it with a gigantic punch! What an attack! That's Build for you! He'll find a way to beat those Smashes without a-"

"Shut up!" Build yelled, quieting Sawa. "You're distracting me! Just sit back and watch-" 

As if to prove his point, the Flying Smash got up from being downed by Build's punch, and struck him right in the face with its giant talons, knocking him onto the ground. 

"Sorry!" Sawa said, apologetically. 

"Ugh, this is terrible," he muttered, as he took out the Diamond Fullbottle and shook it, replacing the Vacuum Fullbottle in his Build Driver. " **Gorilla! Diamond! Best Match! Are you ready?** "

As the Flying Smash prepared for its next attack, Build cranked the Build Driver's handle furiously, as a runner with a clear copy of the Gorilla Halfbody formed in front of him and a runner with the light blue Diamond Halfbody formed behind him. "Build up!" he announced, as the runners slammed onto him. 

" **The Shining Destroyer! GorillaMond! Yeahhh!** " 

As soon as his transformation was complete, he began cranking the Build Driver again, prepping for a finishing attack as the Flying Smash took off into the air, firing pellets at him. " **Ready, go! Vortex Finish!** " 

Build stuck his left hand out, turning all the pellets that were being fired at him into a giant diamond wall, before punching it with his right, sending diamond fragments into it. As the diamonds pelted the Flying Smash, it exploded, making it fall to the ground weakened. 

"He did it! Nice! Turn this way, I need- Oh no!" Sawa said, looking at her camera. "One of the diamond shards broke my lens! Noooo!"

Build sighed, and took out an empty bottle to extract the Flying Smash's essence. "So obnoxious..." he muttered, as Kouta's mom returned to normal. 

"Mom!" Kouta yelled, running from behind the pillar. "Mom! You're alright!"

"Kouta..." his mother said, hugging her son who embraced her, confused. "What... what happened?" 

"You were turned into a scary monster," Kouta said, sniffling. "But the Kamen Rider saved you!" 

"I'm sorry," she said, assuring her son, as she glanced at Build, who, oddly enough, seemed to be content behind his helmet.

"Hey, it's the Kamen Rider!" someone said, up above on the bridge. 

"Someone call a pro hero! The police! Even a Guardian troop! Something!" 

"He must've been attacking that family!" 

"Nonono no! That's far from the truth! You don't know what you're talking about!" Sawa said, coming out from under the bridge. "He just saved them! Okay, so he might have beaten her up a bit to change her back, but-"

"Oh, so he's a woman-beater now!?" 

"And when I thought the Kamen Rider couldn't get any worse!" 

"Wait, you're taking it the wrong way, he has to beat up people to-"

"Please stop digging this hole deeper for me," Build said, as he inserted the Lion Fullbottle into his smartphone, changing it into a motorcycle, and drove off before anyone else could say anything more. 

* * *

"So those people saw what you did, and still thought you were up to no good?" Ryuga said, as Sento returned to working on the Gatling Fullbottle's weapon. Izuku was sharing his Secret Rider Files with Eijiro, Mina, and Pony, and Misora was in the Purification Chamber working on the new Fullbottle. "See? We should be focusing on the organization! When we stop them, all our problems will be solved!" 

"I dunno, Mr. Banjo," Izuku said, looking up at him. "Even with Misora's help, we still haven't gotten any closer to finding Mr. Nabeshima. And even if we find out more about them, I don't think our problems would be gone..."

"Yea, don't remind me-" Ryuga muttered, when the Purification Chamber's ding echoed throughout the Build Shop, causing him to jump in surprise.

"Today's prize! It's done!" Sento said, excitedly as a tuft of hair popped up from his head. He pulled out the orange Fullbottle, which was shaped in the form of a hawk. "So it's a hawk this time? Amazing!" 

As Sento marveled at the new Fullbottle, the Purification Chamber's door moved and Misora popped out. "Tired... Sleepy... don't wake me up, or I'll cut you all," she muttered, walking past everyone and into her room. She closed the door, and immediately snoring could be heard behind it. 

"Tch, would love to show that side to Miitan's fans..." Ryuga said, squinting at the door, while Sento walked to the side of the Chamber. Everyone looked at him, as he inserted the Hawk Fullbottle and the Pyramid Fullbottle onto a strange device in the wall. 

"What's that thing?" Ryuga asked, looking at Sento, who seemed a bit disappointed.

"It's for Best Matches," a voice said, causing everyone but Sento to turn. Souichi had come down the stairs, as he attempted to make a dramatic entrance. 

"I'll say it again... it's for Best Matches."

"That... means nothing to me," Ryuga said, his face blank. "Also, I... don't think that explains anything, either."

"Oh right! We haven't explained what Best Matches are!" Izuku said, butting in before Souichi could say anything else. "You see, the Fullbottles have different compatibilities and power! Like Rabbit and Tank, for example!" 

Izuku ran towards the workbench, and grabbed the aforementioned Fullbottles, and headed towards the device in the wall. "When these compatible combinations are set, this device lights up and shows us what it is! We call them Best Matches!" 

"Steal my thunder, why don't you?" Souichi said, smirking. "Nah, he's on point. What I can tell you also, is that when all the Best Matches are found, something crazy's supposed to happen. What that thing is, we don't know yet. And it's not easy, either." 

"Exactly," Sento said, picking up the Build Driver. "Which is why we need this. That device over there is useful for finding Best Matches here, but the Build Driver's the real star. Initially, it was made just to transform into Build, but I modified it to hunt down the Best Matches while in the field!" 

As Sento said that, Izuku took the Rabbit and Tank Fullbottles, and inserted them into the Build Driver, making it announce " **Rabbit! Tank! Best Match!** " 

"So? What do you think? How you like my modifications?" Sento said, smirking smugly. 

"It's _amazing_!" Pony said, stars in her eyes.

"Yea, it's incredible you're able to come up with all this!" Mina added, and made a thumbs-up.

"Well, I think I could just guess these Best Matches," Ryuga said, taking the Build Driver out of Sento's hands. "Can't be too hard."

"That's a bold thing to say, musclehead," Sento said, snickering, as the others looked at each with a bit of doubt. "Then why don't you try it? How about you find the Best Match for Gatling?" 

He grabbed the Gatling Fullbottle's weapon from the workbench, which was still incomplete. "This is the Gatling Halfbody's weapon, the... somethingatlinger. I've been stuck on making this, since I want it to reflect the Best Match. But I doubt that you would-"

" **Hawk! Gatling! Best Match!** "

"No way!" Sento said, turning around to see Ryuga inserting the new Hawk Fullbottle and the Gatling Fullbottle into the Build Driver. It was clear as day, the Build Driver had reacted to a Best Match. That Ryuga found. 

" _Bravo_!" Souichi said, clearly impressed.

" _Incredible_!" Pony added, clapping her hands.

"How'd you like them apples! That's my sixth sense right there!" Ryuga said, smirking smugly just like Sento was earlier. However, Sento, after his brief shock, started to think of names for the weapon.

"Hawtlinger... no, Hawkgatlinger is a better name, let's use that," he muttered, as he returned to working on the Gatling Fullbottle's weapon, now with a renewed sense of what to make it. 

"How did you know what the Best Match would be?" Souichi said, as he, Izuku, and Eijiro gathered around him.

"Yea, that was amazing! First try, and bam! Best Match!" Eijiro said.

"We've been doing this for months now, and we only found four Best Matches! Not to mention that the Hawk Fullbottle was created _today_!" Izuku said, racking his brain to figure out how Ryuga could've gotten the Best Match.

"Well, if you ask me, to get a Best Match, all you need is an animal and a machine!" Ryuga said, smiling triumphantly. 

"There's no way that kind of childish logic could be right!" Sento said, picking his head up from the workbench. "I've been trying use quantum mechanics to find Best Matches and-"

All the chatter was cut short by a thrown paint scraper that landed blade first into the Purification Chamber's door crack. Everyone turned, and saw a tired, but menacing, Misora, who rung her sleeping mask in her hands.

"I'll cut you if you keep this noise up," she said, making a sinister smile. Everyone stared at her, before giving a very frightened "Sorry." Misora nodded, and went back to her room, and resumed snoring. 

"So do you think you can find any more Best Matches?" Mina said, eyeing the other Fullbottles on the workbench. 

"Sure, let me see what we got," Ryuga said, as he picked up the Deer Fullbottle. He glanced at the other Fullbottles, and picked up the Pyramid Fullbottle. Sento shook his head as he began to draw the Hawk attachments to the Hawkgatlinger. 

"Well, you might have gotten lucky with Hawk and Gatling, but I doubt that you'll get it-" 

" **Deer! Pyramid! Best Match!** "

"Again!?" 

" _Wow_! So that's my Best Match?" Pony said. "Seems real regal!" 

"I have to write this down," Izuku muttered, grabbing the Secret Rider Files and started to jot down notes.

"Funny, I wouldn't think that deer and pyramids would be related at all," Eijiro said, scratching his head. 

"Yea, what's up with some of these Best Matches? I mean, why would cute little rabbits be paired up with heavy artillery?" Mina asked. 

"Eh, it's not like we know, either," Souichi said, leaning against one of the metal pillars. "The Fullbottles are a mystery, after all."

"One that I intend on solving," Sento said, as he looked over his sketches for the Hawkgatlinger one more time. "Hm... wonder what the attack announcement I should give this..."

"Attack announcement? Oh, you mean like what the Build Driver makes?" Mina said, walking over to look at the Hawgatlinger sketches. 

"Yea, it helps let me know when I've gathered enough energy to weaken Smashes enough to extract their essence," Sento said.

"So they're like some of those super moves that pro heroes have?" Eijiro asked.

"I... guess, I never really thought about it like that."

"So that must mean you've got some names for them!" Pony said, joining in. "Like All Might's Smashes!"

"I... don't, but maybe I should... it would make it a little more impressive, not to mention that it might make people more accepting of Build... I'll get to work on making some new attack names after this, then," Sento said, getting up to get more materials to finally finish the Hawkgatlinger.

"I think I got a couple ideas!" Mina said.

"We're brainstorming names? I'll help too!" Eijiro said, as the teens started to clamor together to come up with some new names for Sento to use. 

* * *

The next morning, Sento looked at the list of names and suggestions that the teens had made on the glass board. He chuckled at some of them, like Eijiro's "Rabbit Riot" and Pony's "Antler Action", but some of them, like Mina's "Burning Birdbot" and Izuku's "Tank Down" sounded pretty good.

"So are we finally gonna do something about Nabeshima?" Ryuga said, coming out of his room. "We can't just keep waiting for anything to come up."

"Be patient, Banjo," Sento said, shaking his head. "I've been doing this for months now, and if I've learned anything, it's that there's no point in trying to rush things without thinking." 

Ryuga scoffed, before he plopped himself on the couch. "Yea, well I've been in jail for months, too, so excuse me for not being patient about clearing my name."

While Sento was a little annoyed, he did admit to himself that Ryuga had a point about being in jail for months for a murder that he didn't commit. "I know, but we still don't have many leads. Though I guess considering his connection to Katsuragi, I guess it won't hurt asking Mr. Himuro about him..." 

He picked up his overcoat from his chair. "I'll be back after work, don't get into any trouble, alright?"

"Oh please, what trouble can I get into when I'm stuck here as a fugitive?" Ryuga said flippantly, before being yanked. 

* * *

"Detroit _Smassssssh_!" Izuku yelled, as he punched the air. He grimaced as the bones in his right arm broke once again. For his One for All training, he and All Might have been using All Might's personal gym at Might Tower, since he'd be drawing too much attention at the beach, and All Might's personal gym provided the necessary privacy and endurance needed to handle One for All's blows. He clutched his bruised and battered arm, and muttered, "Dang it, not again..."

All Might and Recovery Girl stood at the side, observing his progress. Recovery Girl shook her head, and walked over to heal Izuku's arm. "Really now, boy, you need to take care of yourself more. Just because I'm around doesn't mean you can keep destroying yourself like this. And you-" she added, turning to All Might, "- you need to do a better job of giving advice to your young ward. Heaven knows what he'll do without it."

"Of course, Recovery Girl," All Might said, sighing. "I still have a lot to learn about being a teacher..."

"No, it's not your fault, All Might," Izuku said, as he began to bend his newly healed fingers. "I'm just not nearly compatible with One for All, even with my Hazard Level. I just... I just need to keep trying, right?"

"Of course, my boy," All Might said, putting his hand on Izuku's shoulder (the one that didn't get shattered, of course). "But for now, let's end today's morning training, alright? You need to take it easy after that healing session." 

Izuku nodded, and went to grab his bag. As chaotic as this week has been, he hoped that something good would come out of today. It's bad enough that he hasn't been making any progress with his training with One for All, and the fact that they haven't found anything about the organization was just as bad. 

* * *

"Nabeshima? Not familiar with anyone with that name," Gentoku said, as he and Sento walked on the observation deck above the Pandora Box room. 

"So Mr. Katsuragi never mentioned that name to you?" Sento asked. Gentoku raised an eyebrow at the scientist. 

"Katsuragi? Hm... Not that I remember. Might've at one point. Why are you asking about Katsuragi?"

"Well... I'm just curious about him. One of my colleagues mentioned him before, and I wanted to know more about him outside of his work on the Pandora Box Observation and Testing Team," Sento said, half-truthfully. "And I thought I might've seen the name Nabeshima concerning him before, but I must've misread something." 

"Hm... Well, the man was of course a genius by every sense of the word. He had earned his place as the head of observation and testing team, and helped usher in some major achievements with the research. But among his colleagues, he earned a nickname. 'The Devil Scientist'."

"'The Devil Scientist'? For what?" 

"Human experimentation," Gentoku said bluntly, much to Sento's surprise. "At least, the mere suggestion for it. Less than half a year before his murder, he had gone to the board and pitched the idea of using the Nebula Gas emitted from the Skywall, and wanted to see the effects it had on human exposure, especially in regards to Quirk development. Naturally, the board was opposed to this, and immediately expunged Katsuragi from his position. I managed to at least convince the board to keep the reason for his dismissal under wraps in respect for his work, though a few outside the board had found out, hence the nickname. The last I heard of him before his death was that he was working as an independent scientist."

"I see... Why are you telling me this?" 

"As I see it, since you're curious about Katsuragi, you'll come across those colleagues who had little fondness for him in the first place. I figure that you should get the clear truth rather than a foggy one," Gentoku said, stroking his goatee in thought. "Besides, I consider his achievements concerning the Pandora Box to have more weight than a mere malicious suggestion. Not to mention that I feel like that with you on the project, you'll provide as much, if not more, valuable contributions to our research." 

Sento scratched his head. Gentoku had a point, considering that many of the papers that they currently had on the Pandora Box were based on Katsuragi's observations and theories. But on the other hand, his ideas about human experimentation and Nebula Gas... could it be? 

"I appreciate the truthfulness, Mr. Himuro," Sento said, nodding his head. "I'll be back to work now."

* * *

Ryuga grumbled as he struggled against the chains binding to the pillar. "Come on, why do you guys keep doing this to me!?"

"To keep you from doing anything dumb, of course," Misora said, scrolling through her phone. The door to the lair opened, and Izuku, Eijiro, Mina, and Pony came down the stairs. 

"We're back," Izuku said, rubbing his sore right arm, which was still sore from today's morning training. "So any news about Nabeshima?" 

"Actually, yes," Misora said, smugly smiling. 

"What!?" Ryuga said, struggling even more. 

"I just got these tips right before you four came in. According to the tip, he apparently worked at Nanba Heavy Industries Ltd. until a year ago. Oh, we even got a cell number!" Misora said.

"Man, your fans are something else!" Ryuga replied.

"Compliments are not getting you unchained, Banjo. Besides, it's time for my afternoon nap," Misora said, stretching and yawning a bit.

"What!? Hey, hey! Aren't we going to contact Nabeshima!?" Ryuga said.

"Yea, it seems like a perfect opportunity to," Mina added. 

"I mean, we should wait for Mr. Kiryu to come back and discuss what we need to do," Izuku said. 

"Yea, he'd probably come up with something!" Pony added, shrugging. 

"Sure, that works," Misora muttered, opening her door. "Plus, not obligated to help right now, since I haven't been paid yet."

Ryuga scowled. More waiting. More and more waiting. He couldn't stand it. He took one deep breath, and began flexing his muscles once more as he struggled. This time, the chains began to creak, and finally broke from the tension of his flexing. The others looked at him in surprise, and he walked over to Misora and grabbed her phone. 

"Then I'll call him!" he said, dialing Nabeshima's number. He held the phone to his ear, and to his relief, someone picked up.

"Is this Nabeshima?" he said, as the others watched him from a distance. 

" _... Who is this? How did you get this number?_ " 

"Does the name 'Banjo Ryuga' ring any bells?" Ryuga said, his left hand clutched to the point that if it were any harder, his hand would bleed. Izuku and the others looked at each other, their shoulders tensed and their breath shallow. This was it, their lead. "Where are you!? You need to prove my innocence right now!" 

" _... I can't..._ "

"What?" Ryuga muttered, his brows furrowed as he began grinding his teeth.

" _They'll hurt my wife and daughter... Faust would kill them._ "

"'Faust'?" Ryuga said, confusedly. 

" _The organization responsible for the experiments they've done to you._ "

"So that's what they're called..." 

The grins on the faces of Izuku and the others grew gigantic. Finally, a name that they could use for the organization. Granted, it wasn't much to go on for the moment, but it was a start. They celebrated silently, Izuku grabbing his journal to finally add in Faust to his notes, Eijiro pumped his fists in victory, and Mina and Pony cheer quietly. Only Misora seemed uneasy with the revelation of the organization's name, as she looked away to the ground and clutched her left arm with her right hand, though the others didn't notice her. 

"So you'll testify if I save your family? Where are they?" Ryuga said, making everyone freeze in the room. 

" _In Seito... district 6._ "

"Seito, district 6... I'll do it, just remember to testify for my innocence when I do!" Ryuga said, hanging up. He turned around, and saw Misora and the others staring at him. 

"Mr. Banjo, that doesn't seem like a smart idea," Mina said, biting her lip. "I mean, what if it's a trap!?"

"Ashido's right," Izuku said, though reluctantly. "I mean, we should really wait for Mr. Kiryu to come and we can come up with a plan-"

"Hell no!" Ryuga said, interrupting Izuku. "I'm done waiting! It's time we start doing something, and if you're all aren't gonna help me-"

He looked around, and saw the chains he had broken through laying on the ground. He grabbed them, and started to walk to the others. 

"Then I'll just do it myself!"

"Not if I can help it!" Eijiro said, trying to activate his Quirk. However, nothing happened. "Dang it, I guess I still need time..."

The other teens just sighed, but were suddenly jolted into quick shrieks as Ryuga pulled them together. 

* * *

"Is that enough for you?" 

The middle-aged horned man turned around, looking at Night Rogue and Meta Bolt. "Now let my family and I go!" 

Meta Bolt laughed harshly, and approached Nabeshima, putting his hand on his shoulder. "Sorry, but there's just one more thing we need to take care of."

"But you promised! I've done your dirty work long enough!" Nabeshima said, as he pulled away from Meta Bolt. Night Rogue quickly stepped towards him though and restrained him. 

"And that's just it. You are done. But the thing is, we can't let people just _leave_ Faust when they want to," he said, shaking his head. "So we have to... take care of a loose end." 

Nabeshima's eyes widened, but before he could attempt to escape, Meta Bolt took his Transteam Gun, and spread a cloud of gas around them. When it cleared up, there was no one left to be seen. 

* * *

"I'm back," Sento said, as he walked down the stairs to the Build Shop. When he looked into the workshop, he froze, and saw Izuku, Misora, Pony, Mina, and Eijiro all chained up to one of the pillars instead of Ryuga. He rushed to unchain the five as fast as he could. "What happened?"

"Well, we finally got a hold of Nabeshima!" Mina said, trying to salvage something out of this situation. "Turns out that the organization he's been working for is called Faust!" 

"Yeah, and he told Banjo that he'll testify for him if he saved his family in Seito!" Pony added. "And when we tried to stop him, he just _chained_ us all up."

"Gah, this is so frustrating! I might've been able to stop if my Quirk was working," Eijiro muttered, as the chains fell off of them. He slammed his fist against the pillar behind him, and much to everyone's surprise, dented it. They took a good look at his hand, which had hardened incredibly, to the point that the edges on his arms were razor sharp, seemingly much more than before, as Eijiro stared at his hand with wonderment. 

"It looks like it's back for you!" Izuku said, as Mina and Pony tried theirs. Mina dripped some acid from her fingers, which ate away at the floor quickly, while Pony's horn flew around the room, and as her horns grew back, they noticed that they were differently shaped than before.

" _Amazing_! My horns are so much better now!" Pony said, hopping up and down. "I was just thinking of how to change their shape, and they just did!" 

"And my acid's a lot stronger than before!" Mina said, though a little more apprehensively. "Which might make it harder to apprehend villains without hurting them, actually..." 

"That's nice, but let's get back on track," Sento said, crossing his arms. "And avoid causing more damage to the Build Shop. So, where is Banjo going? I don't think he'd be able to get anywhere without connections."

"Actually, about that," Misora muttered, stretching her arms after being freed. "He took my phone, so we can track him down through that. And it has Sawa's number, so she might be helping him."

"Really? You think Ms. Sawa would be helping him out?" Izuku asked, raising an eyebrow. "That's a bit crazy, don't you think?"

* * *

Sawa stood around the harbor, looking around to see if anyone was nearby. It was crazy, Ryuga had texted her over an hour ago, asking her how to get to district 6 in Seito. Luckily for her, using her underground freelance reporter connections, she found a boat that would take them directly to district 6's pier. However, Banjo was getting late, and the boat operator was getting impatient. 

"So when this second passenger coming?" the boat operator grumbled, as he looked at his watch. Sawa sweated for a moment, trying to find her words. "Well, you see, they, um..."

"I'm here!" a voice said, trying to sound as if it were old. Sawa turned, and saw Ryuga coming towards her, pretending to be an elderly woman hobbling over with a cane. He was wearing an old flowery shirt, a knitted shawl, and jeans.

"Grandma, I knew you'd make it!" Sawa said, walking over to pretend to hug him. Ryuga stared at her before standing upright, grimacing as if she offended. "Grandma? I'm supposed to be a grandpa!" 

"Really? With those clothes?" she asked, before shaking her head. "Whatever, it doesn't matter. I got a boat for us to use, so we should hurry and-"

"Unauthorized personnel detected, step out of premises or be removed with force." 

The two looked around, and a troop of Guardians approached them. Sawa jumped out of the way, making her way to hide behind some barrels as one of the Guardians rushed towards them, only to be punched by Ryuga who intercepted it. 

"Threat detected, preparing for subjugation."

"Like hell that'll happen!" Ryuga said. He dug through his pockets, and pulled out the Dragon Fullbottle he was carrying, but before he could twist it cap, more Guardians started to attack him, but he dodged their punches. With his grasp tightened around the Dragon Fullbottle, he struck one of the Guardians in its abdomen area, causing a small blue shockwave to ripple from his fist. 

"Huh... so that's what Kasumi's Fullbottle does," Ryuga muttered, marveled at the power he now had. "Well, let's make use of it!" 

Before he twist the cap open again, the Guardians had recuperated, and were surrounding him, guns pointed. "Uh oh..." 

As Ryuga braced himself for the inevitable storm of bullets, a storm of bullets came from behind him, hitting the Guardians, which gave him an opening to escape into an empty warehouse and behind some barrels, joining Sawa. Seconds later, to their surprise, Sento ducked behind the barrels too, holding the gun he had been working on. "What are you doing here?" Ryuga hissed.  
  
"What am I doing? What are you doing?" Sento snapped back. "I told you to not do anything stupid, and look what you're doing right now!" 

"Well no one's doing anything else but just waiting for more Smash attacks and not solving the problem at its core!" 

"Oh like you care! All you want is to clear your name and-"

"Because how can I help other people when I'm stuck in a room!?" Ryuga muttered, silencing Sento. "It's not all about me, you jerk! I want to go back to hero work, to being a boxer, to being a person that Kasumi could be proud of! But I can't do anything when I'm a fugitive!" 

The three sat in silence, as Sento put his hand to his chin thoughtfully. "I'm sorry, I didn't really consider that. But you know, I think you're going at this the wrong way."

"Huh?" Ryuga said, furrowing his brow. 

"You shouldn't just think about being a person that your girlfriend could be proud of. Be a person that you yourself could be proud of," he answered. "Since I don't have memories and all, I hope that I was a person that would help people in need, and I'm working towards that, you know? Save them when they need it? And when they're happy, well, that puts a smile on my face. Not that you can see it, of course, I'm a wearing a helmet and all." 

"Point is, if you're serious about helping people, don't do it out of some misguided attempt to be a person that you think others want you to be. Do it because it's what you want to be," Sento finished. He looked to the side to see the Guardians searching the room with their lights on the rifle, before looking back. "Alright, I'll distract the Guardians, you two go onto that boat and save Nabeshima's family."

"Really?" Sawa asked.

"Well, we're this far in now, might as well go all the way. Besides, if his family's in trouble, we gotta help them, right?" Sento said, as he slapped on his Build Driver onto his waist. He took out the Hawk and Gatling Fullbottles, shaking and inserting them. **"Hawk! Gatling! Best Match!** " "Now go!" 

He sprung up from the barrel, firing the Hawkgatlinger to get the Guardians' attention. He cranked the Build Driver's handle as fast as he could, as runners formed around him, protecting from the Guardians' barrage of bullets. In front was the orange Hawk Halfbody, and behind him was the gunmetal gray Gatling Halfbody.   
  
" **Are you ready!?** "

"Transform!" 

The two Halfbodies slammed together onto Sento, creating his orange-and-gunmetal gray form. His left eye was of a orange hawk swooping in, and his right eye was a gray gatling gun barrel. Orange wings sprouted out of his back, as the Build Driver announced, " **The Rampage in the Skies! HawkGatling! Yeahhh!** " 

Build led the Guardians out of the warehouse, letting Sawa and Ryuga escape the other way. They found their way back to the boat, where the operator had been ducking out of sight. 

"We need to go like, right now, sir!" Sawa said, as she stepped onto the boat, but the operator stopped her. 

"Are you kidding? You just led a handful of Guardians here! Not only that, your second passenger is a wanted criminal! I can't risk this trip. Go find some other way to get into Seito," he said, trying to shoo her away. 

"But we need to-" 

"I said-"

"We'll do it."

The three turned around, and saw a young woman walking towards them with her young son. Sawa recognized her from earlier that day as the Smash victim that Sento had saved. "Hey, you're-!" 

"Sorry about that, he gets a little worried about doing this sort of thing, even though we technically do have a license to cross territories for small cargo. My family's the one that owns this boat," the woman said, smiling and sticking her hand out to shake her hand. "I think helping out the people acquainted with my hero deserve some help, don't you?"

"Yes, ma'am," the boat operator muttered, as he went back to start the boat again. Ryuga sat down on the deck, deep in thought about what Sento said earlier. 

"Be a person that I could be proud of," he muttered, as the boat moved towards one of the small openings in the Skywall's red glow. "Have I really not been someone like that? I mean, everything I've done for the longest time had been for Kasumi... God, it's so easy for him to say something like that, he's got no memory about who he was..."

"That's true," Sawa replied, as she watched Kouta and his mother play a game. "But I think he's on to something, you know? Can't really be the hero you want to be if you're not happy with yourself."

"As if I can be right now," Ryuga said, shaking his head. "With everything that's been happening, I can't really afford to be the person I'm happy to be. But once I save Nabeshima's family, maybe... Maybe I'll figure it out again."

Sawa shrugged, figuring that this was at least a step in the right direction, especially since Sento's words were definitely reaching him. Plus, they were on the road to getting Ryuga's innocence proven, so once that's out of the way, he can probably become a better hero than he had been before. 

* * *

Build fired the Hawkgatlinger at the Guardian troops that had been streaming in. They were growing less in number, but there was still quite a substantial amount of them firing their rifles at him. 

"Alright, I think we can thin this crowd out a lot more!" he said to himself. He took off to the sky, and began to spin the Hawkgatlinger's drum. " **10! 20! 30! 40! 50!** "

Clear energy spherical graphs surrounded individual Guardians on the ground, which followed them no matter how they moved. " **60! 70! 70! 80! 90! 100! Full Bullet!** "

Build pointed the Hawkgatlinger towards the ground, and pulled the trigger. "Take this! Hawk Hurricane!"

Hawk-shaped energy bullets flew out of the Hawkgatlinger's barrels, flying towards all the Guardians on the ground, shredding each and every single one. The amount of damages that the Guardians attained caused them blow up, and as Build landed on the ground amidst the explosions, thinking to himself about thanking Mina for the attack name, was immediately tackled by something decidedly not a Guardian. He turned up to face what had hit him, and saw a brute of a Smash standing over him. It was larger than the Strong Smash, with its body covered in thick metal-like plating. Its hands were comprised of three thick, stubby pipe-like fingers, with port holes on its shoulders that expelled steam. Its head resembled a rhinoceros, though its eyes were more like a mechanical chameleon's, moving all around to scan its surroundings.

Build flew up above the Smash, and despite it having crashed right in him, it was too slow to catch up to him, and clambered after him. He pointed the Hawkgatlinger at the Smash, firing bullet after bullet into its face. It shrugged off the shots, and attempted to chase after Build. 

"Boy, you're pretty resilient!" he muttered. The Smash roared, and to Build's surprise, its horns flew off its face like Pony's, and crashed right into his abdomen, knocking out of the air. "Oooooh, that sucked. I guess you're the... Horn Smash? Ugh, whatever the case is, I guess the Hawkgatlinger's not gonna get through that tough armor of yours, huh? Man, and I just finished this, too..."

He got up, and dusted himself off, before pulling out the Deer and Pyramid Fullbottles, shaking them and inserting them into the Build Driver. "Oh well, I wanted to see how this Best Match worked out, too!" 

" **Deer! Pyramid! Best Match!** "

Runners came out of the Build Driver, the rear runner forming into the golden tan Pyramid Halfbody, and the front runner forming into the cobalt blue Deer Halfbody. " **Are you ready?** "

"Transform!" 

The orange and gunmetal gray armor of HawkGatling was replaced by cobalt blue and golden tan. Build's left shoulder armor was shaped like two pyramids combined into a diamond, and his forearm armor was adorned with three pyramid-like spikes. The armor on the right side of his chest resembled a deer's face, with one protruding horn branching over his right shoulder. His right eye resembled a pyramid, and his left resembled a deer head, with its antler protruding to form an antennae. " **The Royal Family Guardian! Deeramid! Yeahhh!** "

"I've got the winning formula!" Build said triumphantly, doing his signature antennae flick with his left hand. The Horn Smash charged at him, and he raised his left hand, forming a triangular energy shield that it ran into. 

"The shield generation's much stronger, though I can still only make one. I suppose the same is true for the laser drone," he observed, as the Horn Smash punched the shield repeatedly. To his surprise, the shield shattered, and the Horn Smash charged at him again, forcing him to sidestep out of the way. "That broke in fewer hits than usual. I guess you're just that tough, huh?"

Build moved his left hand again, this time forming a small floating energy pyramid. He pointed it towards the Horn Smash, and as it flew towards the Smash it fired a laser. The Horn Smash smacked the laser away, but to Build's surprise, the laser bent and branched out multiple times like a deer's antler, hitting the Horn Smash square in the back in multiple spots.

"Branching lasers? Very useful, though it seems each branch gets smaller," he mused, as his energy pyramid continued to fire branching laser after branching laser at the Horn Smash, which didn't know how to block them, as smacking one away with its armored hands would only allow a different branch of the laser to hit it from behind. With the constant barrage of powerful laser blasts, its once near-impenetrable armor was softening from the heat. 

"It's all over for you!" Build exclaimed, as he cranked the Build Driver's handle. " **Ready? Go! Vortex Finish!** "

"Deer Destruction!" he cried out, as multiple energy pyramids formed around the Horn Smash. Each one fired a laser, which all branched out and struck the Horn Smash. With each one hitting it at once, the Horn Smash couldn't take it, and with one final scream, exploded, knocking it down. 

Build took an Empty Bottle out, and extracted the Horn Smash's essence. As the glow faded away, Build was shocked to see just who the Smash was. "Nabeshima!? Well, that would explain the Horn Smash's look, whatnot with the horn and all... But still, why?"

As Build pondered to himself, he heard a metal container falling somewhere around him. On alert, he scanned his surroundings, trying to keep an eye on Nabeshima at the same time. When several minutes passed, he decided that it was probably something knocked over during the fight, and deactivated his transformation. Unfortunately, this proved to be a poor decision, as a small needle struck him in the back. He wobbled back and forth, sweat dripping off his forehead.

"The hell...? Crap, that must've been poisoned," Sento thought, collapsing to the ground. His sight became unfocused, though he could still see a strange creature that slithered and grabbed Nabeshima with its mouth. Sento tried to turn his head to see where the creature was going, and saw a man dressed in a red leather suit, with gunmetal piping adorning his armor. A green cobra insignia rested on his chest.

As he succumbed to the poison that was now no doubt coursing through his entire body, Sento managed to utter his last conscious observation.

"The... the cobra man..."

**Notes for the Chapter:**

> \- 'ey it's about time I updated right? Sorry, a lot of real life things got in the way (some good, quite a bit of bad), and it's threw off my groove by... by a lot, really. And honestly? I think from here on out, the updates are going to be sparse. That's my own fault, real life and all that. I'm also watching Zero-One right now, and trying to rewatch Build at the same time kinda tires me out.  
> \- If anyone's wondering how this is timeline wise, I'd say that for the most part it's been three days since Ryuga and the others joined Team Build as of this chapter, and that it would be on Thursday-Friday, if I'm right, since the last mentioned day was Sunday, when Izuku tested the Smartphone Fullbottle, and Tuesday would be when Ryuga shows up since that happens two days later. Eventful week they're having, huh? It'll also be like, afternoonish at the beginning to let the younger members of Team Build to be present.  
> \- I know, I know, right now this is really focused on the Build side of the crossover. I'm bothered by it too, but I've been kinda stuck on this for a while now, because well, it is mostly going to be about the Build cast being in the MHA setting. Don't worry, the MHA characters will get bigger roles later on.  
> \- I'm gonna start taking more liberties with character direction and dialogue and the like now. Mostly because I want to avoid a 1-for-1 retread of the plots (plus again, kiiiinda gets tiring rewatching Build and rereading MHA), and with Ryuga having been a sidekick before, I feel like he'd have a heroic sense, but it'll still be a while before he fully comes around. I'll still use important lines and plot points, of course, but now I'm gonna do my best to do more unexpected things.


End file.
